R v Sultana (No.7) - [2025] NSWSC 1102

Supreme Court

New South Wales

Summary available
Amendment notes

Medium Neutral Citation: R v Sultana (No.7) [2025] NSWSC 1102
Hearing dates: 09 July 2025
Date of orders: 14 July 2025 – 18 July 2025;
21 July 2025, 22 July 2025, 24 July 2025.
Decision date: 26 September 2025
Jurisdiction: Common Law
Before: Garling J
Decision:
Guilty of the murder of Dayna Isaac

Catchwords:
CRIMINAL LAW – Murder – Single count of murder – Trial by Judge alone – Circumstantial case – Plea of not guilty – Strangulation by two ligatures – Sexual intercourse with body after death – Crime scene evidence – Evidence of a struggle – Whether alternative verdict of manslaughter made out – Mental element – Specific intent – Effect of intoxication – Case for the accused – Third-party intruder theory – No evidence of a break-in – Where the accused’s post-offence conduct was said to be the result of a panic that he would be blamed for the murder
CRIMINAL LAW – Witness evidence – Expert evidence – DNA evidence – Where a witness being the next-door neighbour of the deceased was able to provide a contemporaneous account of the murder – Where the accused was positively identified by a witness as leaving the scene of the murder immediately after the murder occurred
CRIMINAL LAW – Witness evidence – Pseudonym order – Where an informant has given evidence to the Court of admissions made by the accused whilst incarcerated – Where information provided to the Court by an informant could only have come from the murderer – Prison informer
CRIMINAL LAW – Post-offence conduct – Where the accused’s post-offence conduct demonstrated a consciousness of guilt – Where the accused brought his mother to the deceased’s body – Where the accused drove the deceased’s vehicle to a remote area and set it on fire – Where the accused burnt his clothes following the murder – Where the accused changed his appearance following the murder – Where the accused demonstrated suicidal ideations following the murder

Legislation Cited:
Criminal Procedure Act 1986 (NSW) ss 132(1), 133
Evidence Act 1995 (NSW) s 184
Crimes Act 1900 (NSW) ss 428B, 428C, 428E(1)

Cases Cited:
Shepherd v The Queen [1990] HCA 56; (1990) 170 CLR 573
Liberato v The Queen [1995] HCA 66; (1985) 159 CLR 507

Texts Cited:
Not Applicable

Category: Procedural rulings
Parties: The Crown
Paul Jason Sultana (Accused)
Representation:
Counsel:
Y Prowse (Crown)
Dr G Woods KC (Accused)
Solicitors:
Director of Public Prosecutions (Crown)
Proctor & Associates (Accused)

File Number(s): 2023/17108
Publication restriction: Not Applicable

JUDGMENT

On Monday 14 July 2025, Paul Jason Sultana (“the accused”) was arraigned before me on an Indictment dated that day.
The accused was charged with the murder of Dayna Isaac (“the deceased”), on 16 January 2023, in the State of New South Wales. To this charge, he pleaded not guilty.
On that day, at the request of the accused and with the consent of the Crown, for reasons which I delivered ex tempore, I made an order pursuant to s 132(1) of the Criminal Procedure Act 1986 (NSW), that the accused was to be tried before a judge alone, without a jury.

Procedural Background

The accused was arrested on 17 January 2023 and remanded in custody. He has remained in custody since that time.
The accused was committed for trial to this Court by the Local Court on 23 August 2024.
Upon arraignment in this Court, the accused pleaded not guilty to the charge. He has at all times denied murdering the deceased.
On Tuesday 8 July 2025 and Wednesday 9 July 2025, I heard and gave rulings on various interlocutory matters.
As I was hearing the trial without a jury, it was possible to be flexible about the hearing arrangements, and to allow regular pauses or adjournments to enable senior counsel for the accused, and his solicitors, to consult with, and take instructions from, the accused during the running of the case.
Additionally, it was clear to me that the accused was carefully following the proceedings and regularly took the opportunity to provide his counsel and solicitors with short instructions through passing hand-written notes to them.
No issue was raised with me, nor was anything brought to my attention by counsel for either party, which suggested in any way that the accused was unfit to plead, nor that he was unable to follow the trial and provide instructions.
On the afternoon of the second day of the trial, I adjourned the trial until what would otherwise have been the fourth day of the trial, because the accused said that viewing various photographs, which had been made available to him at his request, had caused him psychological upset. Having regard to the serious allegations which the accused was facing, it was important that he could follow the trial and give instructions which he felt able so to do.
Notwithstanding this issue, I was, and continue to be, well satisfied that the accused was fit to plead, and was capable of, and did, fully instruct his solicitor and senior counsel about matters to be raised in his defence of the charge.

Crown Case – A Brief Overview

The Crown case is that the accused, who was in an intimate relationship with the deceased, had a motive to kill the deceased; that he had the opportunity so to do; that he was heard at, and seen leaving, the deceased’s unit at the time of the murder; that he told his mother what he had done and took her back to the scene; that he then left the scene, burnt the deceased’s vehicle and then engaged in conduct, including intentionally misleading police, to avoid being implicated in the murder.
Further, it is the Crown’s case that the accused, whilst in custody awaiting trial, made a number of admissions to Person A, a fellow prisoner, who was confined in the same unit as the accused.
The Crown accepts that its case, although involving a contemporaneous witness who heard what was happening at the deceased’s unit when she was being assaulted and killed, and also saw the accused at that time, was substantially based on circumstantial evidence.

Case for the Accused – an Overview

Senior counsel for the accused did not challenge in his opening that the evidence in the Crown case establishes that the deceased was murdered in her unit on 16 January 2023. He said:

“[Mr Sultana] recognises that it is obvious that Ms Isaac was murdered by someone, but that someone was not he. He was not the murderer. The actual murderer must have been on the premises, committed the murder, and must have fled unobserved.”

It is now convenient to briefly outline the case for the accused, keeping in mind at all times that the accused is not legally obliged to prove his innocence and that, at all times, the Crown bears the onus of establishing the guilt of the accused of the offence charged beyond reasonable doubt.
The accused denies, and has at all times denied, having committed that murder.
The accused accepts that he knew the deceased and was engaged in the early stages of an intimate relationship with her. He says that he loved her, and that he wanted to have a committed relationship with her.
The accused’s case was that he was in possession of keys to the deceased’s unit and that he attended the unit on the morning of 16 January 2023. He let himself in and fell asleep on the couch whilst watching a movie on the television and awaiting the return of the deceased.
The accused says that he was a sound sleeper and that he was deeply asleep until he was awoken by a loud bang. He called out to the deceased and then looked around the unit. He looked into her bedroom and saw her lying on the bed in an injured state. He collected his phone and charger and fled the scene, taking the keys to the deceased’s motor vehicle, a Toyota RAV4, registration number ANU 04E (“the RAV4”).
The case for the accused is that the murder was perpetrated by an unknown third party during the period when the accused was asleep on the couch in the deceased’s unit, and that the Crown cannot disprove the reasonable possibility that this is so.
He accepts that he did not contact police or an ambulance. He drove around in the RAV4 and, sometime after 2pm, contacted his mother. They returned to the deceased’s unit in the RAV4 but left shortly afterwards. He then, in a panic, burnt the RAV4 in bushland at Castlereagh, and burnt his shoes after returning to the Cranebrook property. He did so because he was convinced that he would be falsely blamed by the police for the murder, given his previous experiences with law enforcement.
Speaking generally, the accused accepts that, at some time on Monday 16 January 2023, he did the various things which the Crown relies upon as evidence of consciousness of guilt, but asserts that those things were done out of panic and fear, rather than as an attempt to cover up the fact that he murdered the deceased.
He denies ever speaking with Person A about anything to do with the charged offence.
In a written note of the directions which the accused submitted should be given, senior counsel submitted that, notwithstanding the accused’s defence that he was not the murderer, the Court would nevertheless give a manslaughter direction on the basis that, if it found that the accused was the person responsible for the death of the deceased, it would be open to conclude that, at the relevant time, the accused was likely to have been so affected by drugs or alcohol which he had voluntarily ingested, that it could not be established beyond reasonable doubt that he held the necessary “… mens rea for murder of intent, or subjective foresight”, and so could only be found guilty of manslaughter.

Background and Context

It is now appropriate to outline the events in greater detail in order to give context to this judgment.
The accused was born in August 1990. At the time of the deceased’s death, the accused was 32 years old and was almost 35 years old at the time of the trial.
The deceased was born in July 1994. She was the mother of two children who were 3½ years old and 15 months old, who lived with her at the time of her death. The deceased was 28 years old in January 2023.
In January 2023, the accused lived at 22 Robinson Road, Cranebrook, with his grandfather, Basil Tsiliris (“the Cranebrook property”).
The deceased lived at Unit 19/8-12 Colless Street, Penrith (“the deceased’s unit”). She had lived there since November 2022. The deceased’s unit was part of a complex of 30 units (“the unit complex”) spread over two or three floors with a basement level carpark.
The deceased and Mikkel Isaac were married in November 2017. The younger brother of the accused, Nathan Sultana, was the best man at the wedding.
It is evident that the accused and the deceased were known to each other for a significant period of time, prior to January 2023. The accused first met the deceased when he lived in a granny flat on a property which the deceased and Mr Isaac occupied briefly in 2018 after they were married.
In March 2021, the deceased and Mr Isaac were arrested in relation to a number of drug supply, firearm supply and criminal group offences. As a consequence of those charges, Mr Isaac was in custody, bail having been refused, at the time the deceased was killed. In November 2022, the charges against the deceased, who had been granted bail, were finalised and she was thereafter subject to an Intensive Correction Order. At that point in time, the deceased and Mr Isaac separated.
It became apparent that the deceased and the accused, sometime in November or December 2022, commenced a relationship. On Christmas Day 2022, the accused attended Christmas celebrations with the deceased at her mother’s house. Her mother, Deborah English, was present, as was the father of the deceased, Garry English, and the deceased’s two children.
By early January 2023, the relationship between the accused and the deceased had become an intimate one, although the relationship was neither a stable, nor an established one.
On Saturday 14 January 2023 (“the Saturday”), the accused stayed the night at the deceased’s unit, although it is not clear at what time he arrived at the deceased’s unit.
During the day, on Sunday 15 January 2023 (“the Sunday”), in a conversation with her mother about the accused, the deceased told her mother that the accused did not have a key to her unit, but that he had started to move his belongings into her unit. The deceased told her mother that she did not want that because she did not want a relationship with the accused. She told the accused to remove his belongings from her unit.
On Monday 16 January 2023 (“the Monday”), the deceased attended a trial shift at a workplace in Penrith at about 7.30am. The work trial was for a half-day, and she left that workplace shortly before 1.00pm. The workplace was near where she lived, and the deceased was observed returning to her unit in her motor vehicle shortly after 1.00pm.
At about 1.10pm or so, a neighbour heard the sounds of an argument coming from within the deceased’s unit. She heard a male voice yelling and a female voice saying “Stop”. The neighbour heard a loud thud noise. She heard a male yelling and further thuds from within the unit. She heard the male yell “Shut up”. She heard the female say “Don’t”, followed immediately by “Stop”. Thereafter, the neighbour heard a very loud scream from a female’s voice. Nothing further was heard from within the deceased’s unit.
A short time later, the accused was observed, by that neighbour, leaving the deceased’s unit and walking down the stairs to the basement level carpark, where he accessed the deceased’s RAV4 and drove away.
At about 2.10pm, the accused telephoned his mother, Janet Tsiliris, and said to her, “It’s bad. It’s bad. It’s bad”. The accused and his mother met up. His mother thought that the accused was acting “really erratic and manic”. She was driven by the accused, in the RAV4, to the unit complex. They both entered the deceased’s unit. Upon entry to the unit, the accused’s mother observed blood in the entryway, damage to a wall caused, she thought, by someone being pushed into it, then observed the deceased, in her bedroom, lying on her back on the bed, clearly deceased. The accused’s mother quickly fled the unit, was picked up by her father, Basil, in a separate car and taken to the Cranebrook property. The accused left the deceased’s unit immediately after his mother had done so and drove away in the RAV4.
At about 3.00pm, the deceased’s neighbour contacted the police. Two police officers arrived at about 3.34pm but were unable to gain entry to the deceased’s unit. They stayed for about 10 minutes before leaving, having seen or heard nothing untoward. At about 4.00pm, the accused’s mother attended at the Penrith Police Station and reported what she had earlier seen.
By that stage, the accused had driven the RAV4 to an area of bushland near Post Office Road, at Castlereagh, and had set the vehicle alight, completely destroying it.
Having transported his bicycle in the boot of the RAV4 to Castlereagh, the accused cycled back to where he was living at the Cranebrook property and proceeded to burn what seemed like clothing in a metal drum at that address.
Ultimately, at about 4.20pm, acting on the information provided by the accused’s mother, police officers attended at the deceased’s unit, and gained access to it through a window from a front patio area. They then unlocked the front door to allow other police to enter the premises.
The deceased was discovered lying on her bed. She had been physically assaulted, with obvious facial wounds, and she had two ligatures, one white and one black, tightly wound around her neck.
There was physical damage to a part of the deceased’s unit, and blood stains or spatters were located in a number of areas of the deceased’s unit.
In the early hours of Tuesday 17 January 2023 (“the Tuesday”), the police attended at the Cranebrook property and arrested the accused. He has been in custody since that time.

Directions of Law

It is necessary in a judge alone trial for the judge to set out the principles of law which are applicable, and which bind the judge in coming to any decision. As well, if the law requires a warning to be given to a jury, then a judge is to take that warning into account in dealing with the matter: s 133 Criminal Procedure Act 1986 (NSW).
I will now set out those principles of law which are applicable, and which will be followed and applied, by me, throughout this judgment.

Overall Duty and Responsibility

It is the Court’s duty and responsibility to consider whether the accused is guilty or not guilty of the charge of murder and to return a verdict according to the evidence which has been admitted in the trial.

Any Obligation to Apply the Law

I am bound to apply the principles of law contained in the directions that I give myself to the facts of the case as I find them to be.

Impartiality

In considering my verdict, I must act impartially and dispassionately. I must not let emotion sway my judgment. Neither prejudice nor sympathy have any role to play in the determination of the charge on the Indictment. My task must be, and will be, undertaken free of prejudice or sympathy.

Burden of Proof

The burden of proof of the guilt of the accused wholly rests on the Crown. That onus rests upon the Crown in respect of each element of the charge on the Indictment. The Crown must prove the guilt of the accused and prove it beyond reasonable doubt.
There is no onus of proof on the accused. He is presumed to be innocent unless and until the Crown proves that he is guilty beyond reasonable doubt. The accused has given sworn evidence denying that he murdered the deceased and has also signed an Agreed Statement of Facts which became an exhibit. He has also made submissions via his senior counsel. By so doing, the accused does not assume any onus of proof. The onus remains on the Crown throughout the trial. The fact that some, or all, of the evidence put before the Court by the accused may not be accepted does not affect the Crown’s onus of proof, and it does not relieve the Crown from proving the guilt of the accused beyond reasonable doubt.
Although the Crown must prove the guilt of the accused beyond reasonable doubt, before making a finding of fact I need only to be satisfied of proof of such fact on the balance of probabilities. Neither party submitted that any fact was an “intermediate fact”, thereby requiring proof beyond reasonable doubt: see Shepherd v The Queen [1990] HCA 56; (1990) 170 CLR 573.
Noting that the accused has given sworn evidence and agreed to a Statement of Facts which is in evidence, in accordance with Liberato v The Queen [1995] HCA 66; (1985) 159 CLR 507, I remind myself that, first, if I accept the evidence given by the accused that he did not murder the deceased, then I must acquit him.
Secondly, even if I find difficulty in accepting the part of the accused’s evidence denying that he murdered the deceased, but I think that it might be true, then I must acquit the accused. That is because if it is a reasonable possibility that the accused was not responsible for the murder of the deceased, then the Crown has not proved its case beyond reasonable doubt.
Thirdly, if I do not accept the accused’s evidence that he did not murder the deceased, then I must put that evidence to one side and consider whether the Crown has, on the basis of evidence which I accept, proved the guilt of the accused beyond reasonable doubt. In other words, the fact that I do not believe the accused’s denial that he was the murderer does not mean that he was.

Evidence of Witnesses

I must consider and assess the evidence given by the various witnesses, including the accused, and decide whether they are telling the truth, whether the evidence is reliable, and whether I accept their evidence. My ultimate decision as to what evidence I accept and what evidence I reject, may be based on a range of matters, including the content and the context of what a witness had to say, the manner in which the witness said it, and the general impression which any witness made upon me in giving evidence.

In considering whether to accept the evidence of a witness, I am not obliged to accept the whole of the evidence of any one witness. I may, if I think fit, accept part, and reject part, of the evidence of the same witness. In other words, the fact that I do not accept a portion of the evidence of a witness does not mean that I must necessarily reject the whole of that witness’ evidence. I can accept part of the evidence of a witness if I think it is worthy of acceptance.

Expert Evidence

Two witnesses were called by the Crown to give expert evidence, Dr Issabella Brouwer, a forensic pathologist, and Ms Mhorag Campbell, a forensic biologist.
An expert witness is a person who has specialised knowledge based on their training, study or experience. Because they have such knowledge, they may express an opinion on relevant matters that fall within their expertise.
To the extent that there is any conflict within, or doubt about, the evidence of an expert, it is for me to decide which part, or parts, of the evidence of the experts I accept, and which part, or parts, I reject. I must remember that any expert evidence relates only to part of the case, and that whilst it may be of assistance to me in reaching a verdict, I must reach my verdict having considered all of the evidence which is applicable.
If, having given the matter careful consideration, I do not accept the evidence of any of the experts, then I do not have to act upon the evidence of the expert in question. I do not have to accept even the unchallenged evidence of an expert.

Consciousness of Guilt

The Crown relies upon certain features of the conduct of the accused as evidencing a consciousness of guilt of the unlawful killing of the deceased. These include the accused’s failure to call either the police or an ambulance to the scene, his decision to bring his mother to the deceased’s unit to observe the body, the burning of the deceased’s car by the accused, the burning of some personal material in a barrel at the Cranebrook property by the accused, the accused drastically changing his appearance by shaving his head and beard on the afternoon of 16 January 2023, and that the accused sent a text message and said things which were intended to positively mislead the recipient, or the police, about his knowledge of, and involvement in, the commission of the offence (together “the post-offence conduct”).
If I am satisfied, as a matter of fact, that any or all of the post-offence conduct occurred, then I direct myself as follows:

that such post-offence conduct does not on its own and without more, prove the guilt of the accused of the unlawful killing of the deceased;

I must be satisfied that the post-offence conduct related to, or was connected with, the unlawful killing with which the accused is charged; and

I must be satisfied that the reason the accused engaged in some or all of the post-offence conduct, was that he was concerned to avoid being implicated in the death of the deceased, for which he is now on trial.

If I am satisfied of each of these matters, then I can consider those parts of the post-offence conduct which have been proved and my conclusion about them and take them into account as circumstances which evidence a consciousness of guilt of the accused for the unlawful killing of the deceased.
Of course, in considering these matters, I need to keep in mind that people do not always act or behave rationally, and that the post-offence conduct here may be explained in other ways: the accused may have panicked having seen the body of the deceased in the unit, he may have wanted to escape being unjustly accused, or he may not have trusted police to investigate him without prejudice or bias.
If the post-offence conduct has been engaged in for some reason other than being implicated in the offence for which the accused is now on trial, then I cannot use it as evidence of the guilt of the accused, and I must put it to one side for the purpose of my decision-making.
The Crown also relies on the accused’s consciousness of guilt of the offence of murder, because of the evidence that he deliberately told lies, which constituted saying things which he knew to be untrue, to the police on the day of his arrest in the course of a recorded interview, about where he was, what he knew about the deceased and what he was doing on the Monday.
I remind myself of the principles of law by which I am bound when considering this issue, namely that I must be satisfied:

that the particular statements made by the accused were deliberate lies – that is, false to the knowledge of the accused at the time he made the statements;

that the only explanation for the lies is that the accused knew that the truth of the matter about which he had told lies, was relevant to the death of the deceased, or some significant circumstance or event, connected to that death, and would implicate him in the unlawful killing of the deceased; and

that the accused feared that telling the truth might reveal his guilt of the unlawful killing of the deceased.

Circumstantial Case

As I have earlier mentioned, the Crown case against the accused is, in significant part, a circumstantial one. Because of this, I cannot return a verdict of guilty upon the charge unless the circumstances are such as to be inconsistent with any reasonable hypothesis other than the guilt of the accused.
To enable me to be satisfied beyond reasonable doubt of the guilt of the accused on the charge, it is necessary that the Crown persuade me that the guilt of the accused is a rational inference, and that it is the only rational inference that the circumstances would enable me to draw.
This means that the Crown must exclude all reasonable hypotheses consistent with the innocence of the accused. For a hypothesis to be a reasonable and rational one, it must rest upon something more than mere conjecture or supposition. A bare possibility of innocence does not prevent a conclusion that the accused is guilty of the offence, so long as the inference of guilt is the only inference open to a reasonable person upon a consideration of all of the facts and evidence.
In deciding whether there is a hypothesis reasonably open on the evidence in the Crown’s case that is consistent with the accused’s innocence, all of the circumstances established by the evidence are to be considered and weighed. The evidence is not to be looked at in a piecemeal fashion but is to be considered as a whole.
I remind myself that, in a circumstantial case, each fact can inform an understanding of the significance of other facts. Therefore, it is the understanding of the combined significance of all the facts which informs the issue of whether the Crown has proved the guilt of the accused beyond reasonable doubt in respect of the offence charged.
There are other principles of law by which I am bound, including how to deal with particular types of evidence, including giving myself a warning about accepting some evidence. It will be convenient to articulate these principles when dealing with the evidence.

Offence of Murder

The Crown’s case is one of murder. In order to succeed in proving its case, that the accused murdered the deceased, the Crown must persuade me of each of the following elements beyond reasonable doubt:

that on Monday 16 January 2023, the accused, Paul Sultana, strangled the deceased, Dayna Isaac, thereby causing her death; and

that the accused’s conduct in strangling the deceased was deliberate (that is, not accidental or involuntary); and

that at the time of the strangulation, the accused intended to kill the deceased, or else intended to cause her grievous bodily harm (that is, really serious physical injury); or

if neither specific intention is proved, the accused acted with reckless indifference to human life.

As I have earlier noted at [26], the accused submits that if, contrary to his case, I am satisfied that he strangled the deceased, then it would be open to me on the evidence, to accept that, at the relevant time, the accused was so affected by drugs and alcohol which he had taken, that the Crown has not proved the necessary subjective intention for murder, including any subjective foresight, to enable a finding of reckless indifference to human life. If I was not so satisfied, the accused submits that I would need to consider a verdict of manslaughter on the basis that the deceased was killed by an unlawful and dangerous act.

Outline of Relevant Locations

It is convenient to provide a description of the geographical area and a description of the crime scene and its surrounds by way of context.
The unit complex, in which the deceased lived, consisted of a two to three-storey block of units, with 30 units in total. The unit complex was at 8-12 Colless Street, which runs in a generally north-south direction. It is situated on the south-eastern corner of Colless Street and Barber Avenue, which runs in a generally east-west direction.
The front pedestrian entrance was located on the western facade of the unit complex on Colless Street. A driveway leading from Colless Street down to the basement level carpark was located on the southern aspect of the complex. The complex featured a central podium which was a common area above the carpark (“the central podium”). The central podium included some areas of garden. It was largely paved. Access could be gained through a weatherproof glass structure, descending from the central podium to the carpark.
The deceased’s unit was No.19. It was located on the southern side of the central podium, and it shared an entrance hallway and foyer with unit No.18, which was also on the ground floor, and as well with two other units which were situated directly above each of units 18 and 19. Both units 18 and 19 comprised a patio fronting onto the central podium, sometimes referred to as a veranda, a lounge, dining room and kitchen area adjacent to the patio, and two bedrooms at the back of each unit, with windows looking south over the driveway. The motor vehicle entrance into, and exit from, the carpark was through an automatically operated grill-style door which was located directly beneath the deceased’s unit.
There were no CCTV cameras located within the unit complex although a CCTV camera existed at 16 Colless Street, another block in the immediately surrounding area, but which was to the south of the unit complex.
Between the patio immediately at the front and forming part of the deceased’s unit, and the central podium area, there was erected a timber screen containing horizontal timber planks, on the inside of which was a vertical bamboo screen. No.18 contained an identical floor layout and arrangement (but in mirror image) to that of No.19, but without the bamboo screen which had been erected at the deceased’s unit.
The entrance to the carpark was via an enclosed staircase structure which was no more than about 10 metres from the deceased’s unit. That entrance was glass on all sides. Accordingly, there was a clear view of people entering that stairway access from the central podium area. The door made a distinctly audible sound when it was opened.
Inside the deceased’s unit, there were two bedrooms. One was a larger bedroom to which an ensuite bathroom was attached. The deceased used that as her bedroom. It had a double bed in it and some other furniture. The second bedroom was smaller and was used for the deceased’s two young children to sleep in.
Between the bedrooms and the living area was a small laundry and an internal bathroom.
Generally speaking, if one entered through the front door of the deceased’s unit, the bathrooms, laundry and bedrooms were to the left, (or south) and the living areas – being the lounge, dining area and kitchen, with access to the patio – were to the right (or north).
Colless Street runs in a generally north/south direction. The unit complex is on the eastern side of Colless Street, between Barber Avenue to the north and Lethbridge Street to the south. Access at the northern end of Colless Street is from High Street in Penrith, and access to main roads heading in all directions can be gained from the eastern end of Lethbridge Street to the south of the unit complex. 16 Colless Street, where the CCTV is located, is on the north-eastern corner of Lethbridge Street. The unit complex is located within a block of the Nepean Hospital complex, and directly opposite the Penrith High School grounds.
The workplace the deceased attended on the morning she was murdered, was situated at 29 York Road, Jamisontown, which is about 2.5km from the unit complex. It takes around five minutes to drive from the unit complex to that workplace.
As earlier noted, the accused lived with his grandfather, Basil Tsiliris, at the Cranebrook property, which is about 5.5km to the north of the deceased’s unit complex. It is approximately a 10 minute drive or a 20 to 30 minute bike ride between the two locations.
The area of bushland off Post Office Road, Castlereagh, where the deceased’s car was found in a burned-out state, is about 9km north-west of the Cranebrook property. It is approximately a 10 minute drive from the Cranebrook property to that area. The car was found in an isolated bushland area about 100m or so from Post Office Road.

Involved Individuals

It is also convenient here to identify a number of individuals who were central to the events surrounding the death of the deceased.

The Deceased’s Family

As earlier indicated, the deceased’s mother, Deborah English, was close to her daughter and to her two grandchildren. She was separated from the deceased’s father, Garry English.
The deceased had a number of conversations with both her mother and her father at various times in December 2022 and in January 2023 about the existence, and state of, her relationship with the accused.
The deceased spent the Sunday with her mother and her children. Ms English stayed that night at the deceased’s unit.
Mr Garry English also had a number of conversations with the accused at various times, including a telephone call on the Monday, and was present at the unit complex when informed by police of the deceased’s death.

The Family of the Accused

The mother of the accused is Janet Tsiliris. She spoke with the accused on the Monday, visited the scene of the murder, and later reported it to the police. Janet Tsiliris lived in Hope Street, Penrith, which was about 450m from the deceased’s unit.
The accused’s grandfather, Basil Tsiliris, lived at the Cranebrook property and was involved, but only in a peripheral way, with the events on the day of the murder.
The brother of the accused, Nathan, was the best man at the wedding of the deceased and Mikkel Isaac. He was not involved with any of the events surrounding, or on the day of, the deceased’s death.

Mikkel Isaac

Mikkel Isaac was the husband of the deceased although the two were separated at the time of her death.
At the time of the murder, Mr Issac was in custody. He knew the accused, and was close friends with the younger brother of the accused, Nathan. He was granted conditional bail shortly after the murder in January 2023 and was ultimately sentenced for various drug-related offences in September 2023.
Although they were separated, Mr Isaac had a number of conversations with the deceased in January 2023 about her relationship with the accused. Mr Isaac denied murdering, or causing or arranging the murder of, the deceased. There was no evidence that he was involved in the death of the deceased in any way at all.

Kelly Ryan

Ms Ryan was a neighbour of the deceased and lived in the adjoining unit, No.18. Ms Ryan’s unit was identical in layout to that of the deceased and was entered from one side of the common hallway. It was a mirror image of the deceased’s unit. The deceased’s unit was entered from the other side of that common hallway. She is the only witness who can report on contemporaneous events which she heard and saw at the time that the deceased was murdered.
Ms Ryan’s partner, Ms Tara Kennedy, also lived in No.18, although she was not at home at the time of the murder. She returned home shortly after the murder.
Ms Ryan was the person who alerted police as to what she had heard, in response to which an initial police visit took place.

Sequence of Events Leading up to the Death of Dayna Isaac

It is necessary to make findings of fact about the events on the Sunday, which was the day before, and as well on the Monday, which was the day the deceased was killed. As I have earlier directed myself, these findings of fact are made on the balance of probabilities, although, when I have been satisfied of a fact beyond reasonable doubt, I have recorded my satisfaction to that extent.

Movements of the Accused prior to the Death of the Deceased

CCTV footage, adjusted to the correct time, demonstrates that, on the evening of the Sunday, the accused was at the Cranebrook property. At about 11.52pm, he left the property on a motor-scooter and returned at about 2.03am on the Monday morning. Shortly thereafter, at 2.14am, he left the property on a bicycle.
At 8.52am, the accused returned to the Cranebrook property on his bicycle and gained access by climbing over a side fence into the carport area. Eight minutes later, at 9.00am, the accused is seen, again, leaving the Cranebrook property on his bicycle. As he left the property on this final occasion, the accused was carrying some red rope and a roll of tape of a kind often used to seal packing boxes (which was referred to in evidence as “box-tape’).
The accused is observed from a variety of locations fitted with CCTV cameras riding his bicycle in a generally southerly direction towards Penrith and then in the direction of the deceased’s unit. At about 9.17am, the accused is observed from a camera at 28 Coombes Drive, Penrith, which is about 1km north of High Street in Penrith. At about 9.23am, the accused is observed riding in a generally easterly direction along High Street, Penrith and is captured by CCTV turning from High Street to ride south on Colless Street in the direction of the deceased’s unit at 9.25am. That CCTV footage is taken from the Ambulance Superstation, which is located on the Great Western Highway near to, but opposite, the corner of High and Colless Streets, Penrith. There is no view from that CCTV camera in a southerly direction along Colless Street to the unit complex.

Movements and Activity of the Deceased

At about 1.01pm, the deceased is observed by CCTV located at 16 Colless Street, Penrith, driving north in her RAV4 towards her unit complex.
According to the records held by Optus, the service provider for the deceased’s mobile telephone, at 1.08pm a voice call was initiated from the deceased’s mobile to a party described in evidence as “Recruitment Contact”. I am satisfied that this call related to the work trial which the deceased had undertaken that morning. As this call returned a call received at 1.01pm from the “Recruitment Contact”, I am satisfied, on the balance of probabilities, that the first call was not answered. It had occurred whilst the deceased was driving in her RAV4. It lasted about 20 seconds. It was followed at 1.01pm by an SMS, or text message, received by the deceased when her mobile phone was connected to the tower at the Nepean Hospital, which is one block away from the deceased’s unit.
Having regard to this sequence, I am satisfied that the phone call was in fact initiated by the deceased at 1.08pm to the “Recruitment Contact” to return the earlier call. The call lasted 174 seconds (that is, just under three minutes) and terminated at about 1.11pm. The deceased must have been alive at that point in time. I am satisfied that when the call was made, she had arrived at the unit complex and was either walking to, or else already inside her unit, although the actual location is not important to this narrative.

I am satisfied that it was at about, or immediately after, the time the 1.08pm phone call ended when Ms Ryan started hearing banging, raised voices and a female screaming from Unit 19, the deceased’s unit. I refer below to the detail of Ms Ryan’s account.

Ms Ryan

Ms Ryan, the deceased’s neighbour, was working from home. At a time after 1pm, she took a break from her work.
At 1.21pm, Ms Ryan sent a Facebook message to her partner, Ms Kennedy. It read:

“I’m pretty sure I just heard the neighbour beating the shit out of his missus – you should have heard the screaming. I was on a call so I came out when I got off and it’s quiet, but I can hear him telling her to shut the fuck up.”

Given the time (about 1.11pm) when the deceased’s phone call finished, and the time (about 1.21pm) when Ms Ryan sent her message noting that it was quiet, the probabilities are that the deceased was murdered in that 10 minute period.
Shortly after that, Ms Ryan observed a male whom she recognised, and later identified to police, as the accused, wearing a black baseball hat, sunglasses and a black t-shirt leaving the deceased’s unit with what she described as a green Woolworths shopping bag in his hand, and walking calmly down to the carpark.
At 2.19pm, Ms Ryan sent a message to a work colleague, which read:

“I feel like a horrible human – on my break I listened to my neighbour get flogged by her partner, he has left now and they are only new to the complex so I don’t know either of them … I didn’t do anything because I need to be mindful of the fact Eric [her pet dog] is here home alone when we go to the office.
I honestly don’t know how I feel at the moment.”

Movements and Activities of the Accused following the Death of the Deceased

At 1.26pm, a CCTV camera at 16 Colless Street, and the one further south at 24 Colless Street, captured the accused driving south away from the unit complex in the deceased’s RAV4. At that stage, the accused has the same facial appearance as can be seen in the footage of him riding his bicycle towards the deceased’s unit.
According to the Cellebrite download from his mobile telephone, the accused turned his phone on at 2.02pm, and a connection was then established to the Optus network at the phone tower at 86 Palmyra Avenue, Willmot, which is about 11km away from the deceased’s unit, generally to the north-east.
Between 1.57pm and 2.27pm, a period of approximately 30 minutes, the accused is captured by various CCTV cameras driving the RAV4 in the area of Shanes Park and Willmot. He is seen driving into Resolution Avenue, Willmot, and a few minutes later driving out of Resolution Avenue, which is a dead-end street. A close and life-long friend of the accused, Mr Glenn Dyer, lived in Resolution Avenue. The accused telephoned him at 2.03pm, whilst he was halted in Resolution Avenue, but the call was not answered.
At 2.10pm, whilst still driving the RAV4, the accused made a telephone call to his mother, Janet Tsiliris, repeating the phrase, “It’s bad. It’s bad. It’s bad”. The accused is clearly, at that time, driving the RAV4 back in the direction of the unit complex on Colless Street. As he made his way back towards the unit complex, the accused must have met his mother, who entered the passenger seat of the RAV4. This meeting is not captured by CCTV, and so the precise location is unknown.
At 2.27pm, the CCTV camera at 16 Colless Street captures the accused and his mother driving in a northerly direction towards the unit complex.

The Accused Returns to the Deceased’s Unit

Ms Ryan heard the noise of the access door at the central podium from the carpark being opened. She saw the accused and an older woman whom she thought, from their interactions, was his mother, walk to the door to the deceased’s unit. She heard the door to No. 19 open, and the older woman said:

“Oh my God, what have you done? You can’t fix this. I can’t be here.”

She then saw the accused’s mother leave very quickly. Within a minute, she heard the front door of the deceased’s unit being closed and locked and saw the accused leaving.
At 2.31pm, Janet Tsiliris is observed from CCTV footage to be walking south on Colless Street. The accused is seen driving south in the RAV4 and drives past Janet Tsiliris at the intersection of Lethbridge Street. Ms Tsiliris then gets picked up in a black sedan being driven by her father, Basil Tsiliris.
Shortly after the accused and his mother left the deceased’s unit, Ms Ryan knocked on the deceased’s front door and received no response. She walked down to the carpark and saw that the deceased’s car was not there.

First Visit by Police to the Deceased’s Unit

At 3.02pm, Ms Ryan made a telephone call to the Penrith Police Station expressing concern for the welfare of the deceased.
At 3.34pm, police arrived at the unit complex and spoke with Ms Ryan. They then knocked on the door of the deceased’s unit but received no answer. The police officers looked around for signs of any disturbance but found none. They left a Victim Welfare Check card under the door.

Remaining Sequence of Events

After the accused left the unit at 2.37pm, he commenced driving north in the RAV4 in the direction of the bushland at Castlereagh.
Sometime after 2.47pm, the accused drove the RAV4 vehicle into bushland off Post Office Road at Castlereagh and deliberately set it alight.
I am satisfied that the fire was started between 3.10pm and 3.15pm. At 3.33pm, the accused is captured on CCTV cycling south past 94 Tadmore Road, Cranebrook, which is about 5km or so from Post Office Road.
Between 3.33pm and 4.08pm, the accused is seen from a number of CCTV cameras riding his bicycle south, from the direction of Castlereagh, towards the Cranebrook property. He is shirtless and carrying a green Woolworths shopping bag which hangs from the handlebars of his bicycle.
Sometime after the accused returns to the Cranebrook property, a neighbour observed smoke coming from the backyard of the accused’s house and smelt burning material.
At 3.48pm, Basil Tsiliris drove Janet Tsiliris to the Penrith Police Station. At about 4.00pm she reported what she had seen at the deceased’s unit to the Penrith Police Station whilst in the company of her friend, Shannon Hauser, who had travelled separately to the police station to support Ms Tsiliris.

Second Visit by Police to the Deceased’s Unit

Following upon that report from Ms Tsiliris, at about 4.20pm police officers attended the deceased’s unit. An officer gained access to the deceased’s unit through the window from the front patio into the dining area. Police found the deceased and commenced their investigations.

Communications Between the Accused and the Deceased’s Father

At about 4.33pm, the deceased’s father, Garry English, having unsuccessfully attempted to call the deceased on a number of occasions, telephoned the accused. He was told by the accused that he had not heard from the deceased. The accused told Mr English that he had:

“… been at home because she doesn’t want to be with me”.

Around about 5.30pm, Mr English drove to the deceased’s unit, where he was informed by the police of the deceased’s death. Shortly after that, he received a telephone call from the accused, which he did not answer. At 5.46pm, the accused sent a text message to Mr English, saying:

“What’s going on? Where is she?? Is she OK?? Is she in hospital??”

The Arrest of the Accused

In the early hours of the following morning, being the Tuesday, the accused was found asleep at the Cranebrook property, where he was arrested by the police.
The accused was taken back to Penrith Police Station. After a time-out period, and after he received legal advice, and noting that he was not obliged to do so, the accused agreed to participate in an electronically recorded interview with Detective Senior Sergeant Gilbert and Detective Senior Constable Pellegrino. The interview commenced on the Tuesday, shortly before 1.00pm and concluded at 2.02pm. It will be convenient to refer to this interview as the “Recorded Interview”.
In his evidence at the trial, the accused said that he had intentionally lied to police in the course of the Recorded Interview.

Evidence in the Crown Case

Crime Scene Description and Police Observations

It is now convenient to turn to evidence found at the scene by police officers on the Monday which is supplemented by the scientific opinions as to what forensic testing showed.
The first police officers who visited the scene after the accused and his mother had left the deceased’s unit, were Constable Abbey Coleman and Senior Constable Andrew Hayward, who arrived at the unit at about 3.34pm. They heard nothing from within the unit. They knocked on the door and announced that they were the police. There was no response. They continued to knock but, again, received no response. The front door did not show any sign of a break-in, or any damage at all. They could not hear any noise coming from within the unit. Having left a notification card, they left the unit complex. On the way out, they examined the front patio to make sure that there was nothing untoward. They observed that the blinds appeared undisturbed and there was nothing out of order. There were certainly no signs of any break-in.
Those two officers returned that afternoon at about 4.20pm. They made a decision to enter the unit. Senior Constable Hayward found some difficulty in so doing. He climbed up to the balcony of the upstairs unit, above the patio area of the deceased’s unit, and then using such supports as were available from that balcony, he swung his feet through the gap above the top of the bamboo screen at the front of the deceased’s unit and lowered himself to the floor. The space through which he had to pass his body was about 30-40cm in height. He managed to slide through that gap and drop down onto the floor.
He checked the sliding balcony door and found that it was locked. He then observed that there was a window beside it which had an air-conditioner duct fitted to a part of it. He removed the flyscreen from the window and managed to open the window, which was unlocked. He then entered the unit by crawling through the window. He had cut his left arm on the bamboo as he entered, and his blood was deposited on the windowsill.
The significance of this evidence is that it is clear from the observations of both of these police officers that there had been no break-in or forced entry into the deceased’s unit, either through the front door or else through any entrance via the front patio.
The windows at the back of the deceased’s unit were not suitable to be used as an entrance or exit, unless the intruder had a long ladder. These rear windows were intact and undamaged when photographed by the police. No long ladder was found. There is no evidence that there was any forcible break_‑in from that entrance point to the unit. I do not regard there being any possibility at all that access was gained to the deceased’s unit from these rear windows.
The deceased’s unit showed evidence of a violent struggle occurring inside the unit. The front door was not damaged, from which I conclude that, at the time entry was gained through that door, it must have been unlocked, or else had been opened by the deceased. Directly opposite the front door, on a plasterboard wall, is a significant indentation which, in length, is about 0.8m and commences about 200mm above the floor. It clearly indicates a round shape consistent with the body of a person being shoved forcefully backwards into that wall.
The area on the tiled floor between the front door and the couch contained a number of blood smears and drops. It appears that, at a point after the blood was smeared on the floor, a child’s soft chair came to be in place over the blood smears.
The blood smears and drops continued towards the deceased’s bedroom. Blood splatter is identified on the door to the bedroom. Also on that door, towards the lower corner, away from the hinged edge, there are two palm prints which were matched to the deceased, which are observable in the blood stains at both Marker D and Label F1. The blood on that door was described without challenge, and I accept accurately, by Mr Ben Reid, a crime scene officer with the NSW Police in this way:

“A. …if you reference to marker D in particular, that is what we’d call … that would be a blood stain – blood splatter. Blood splatter is created when force is imparted on a source of liquid blood outside the body. At marker D, it was noted that several of the blood stains had very small air bubbles in them. We then performed a test for saliva on one of these blood stains which came back positive, so this would be an indication that it’s likely what’s called ‘aspirated blood’, so blood projected from the mouth.”

Mr Reid’s evidence was that he observed a transfer blood stain in the region which was marked “F1”, with what looked to him like friction ridge detail, which represented either an imprint of fingers or a palm. What he observed at F1 were later identified as palm prints from the right hand of the deceased.
The deceased was found lying on her bed. A pink lamp, with part of the white cord attached to it, was found lying on the bed next to her. Her black shirt had been pushed up to the lower level of her breasts. She was lying on her back with her legs bent at the knees and hanging over the edge of the bed. Around her lower legs were her black pants and underpants. She was naked in the area between the lower edge of her black shirt down to her ankles. Her trousers and underpants were found pushed down beneath her knees.

Post-Mortem Examination – 18 January 2023

Following the discovery of the body of the deceased, and its removal from the scene, a post-mortem examination was conducted on Wednesday 18 January 2023.
At the commencement of the post-mortem examination, it was observed that the body of the deceased had been removed from her unit in the condition in which it had been first found. The clothing in which she had been dressed, which on the bottom half of her body had been pulled down towards her ankles, remained in that position at the start of the post-mortem examination. As well, the two ligatures which had been present when the body of the deceased was discovered at her unit, were still in place and wrapped around her neck at the commencement of the examination.
On examination, it was observed that there was dried blood present on the face, arms and hands of the deceased, and that there was blood or blood-stained material at the orifice of the deceased’s left and right nostrils.
The forensic pathologist described in her written report, the features of the ligature strangulation of the deceased in the following way:

“FEATURES OF LIGATURE STRANGULATION
(i)    The Ligatures:
1.    Two ligatures were present in situ around the neck.
2.    The ligatures consisted of two separate electrical cords.
3.    The electrical cords wrapped at least thrice around the neck, creating tight, closed horizontal loops.
4.    There was a black electrical cord ligature on the upper part of the neck. On removal of the ligature, it measured approximately 190 cm in length. The ligature was intact, with the plug and receptacle present at the ends of the ligature.
5.    There was a white electrical cord ligature on the lower part of the neck below the black cord. On removal, the ligature measured approximately 137 cm in length. The ends of the white electrical cord had been cut before examination, exposing the cord’s internal wiring.
6.    No knot(s) were present in the ligatures.
7.    The black electrical cord ligature’s ends were at the back of the neck.
8.    The white electrical cord’s ends were on the right anterior-lateral aspect of the neck, with the longer loose end of the ligature looped under the black electrical cord, the end pointing backward on the right side of the head. The other end of the white electrical cord was short and present close to the neck between the loops of the black ligature. The short end pointed forward.
9.    Strands of the deceased’s hair were caught between the ligatures’ loops.”

The ligatures were removed and handed to the police by the forensic pathologist. The injuries associated with the ligatures were then identified and described in the written report in this way:

“(ii) Ligature Associated Injuries:
1.    Multiple minimally indented ligature mark furrows extended around the neck.
2.    The ligature mark furrows had a mainly pale appearance with erythematous red linear markings in between. Blistering was present on these linear markings on the left side of the neck. The red markings and blistering of the skin are in keeping with the pinching of the skin between the ligature strands as it was wrapped around the neck.
3.    No patterned markings of the depth of the ligature furrows were noticed in keeping with the overlying ligatures.
4.    Anteriorly, the ligature abrasion extended transversely across the neck at the level of the thyroid cartilage with an overall width of 4cm and situated 1.5m above the heel of the left foot. Four ligature furrows could be identified on the skin within this area, measuring between 0.6cm and 0.9cm.
5.    The ligature mark was horizontal primarily on each side of the neck and did not appear to extend upwards.
6.    On the right side of the neck, the ligature mark was 9.5cm below the tragus of the right ear. On the left side of the neck, the ligature mark was 9cm below the tragus of the ear. The ligature mark’s overall width on the neck’s left side measured 4.5cm.
7.    On the posterior aspect of the neck, the ligature marks formed a broad pale area measuring 4.5cm in width. Individual ligature furrows could not be appreciated within the pale area.
8.    There was a 0.5cm x 1.5cm abrasion of the anterior aspect of the neck in the midline below the ligature furrows.
9.    Three scratch-type abrasions were noted on the right side of the neck below the ligature furrows measuring between 0.4cm and 0.5cm in length.
10.    There was a 1.5cm x 1 cm blue-coloured bruise on the left side of the neck below the angle of the jaw and in the upper part of the pale area caused by the ligatures.
11.    There was a 2cm x 2cm ill-defined, blue coloured bruise on the left side of the neck below the ear.
12.    There was a 1cm x 2.5cm blue-coloured bruise on the left side of the neck below the ligature furrows at the level of the thyroid cartilage.”

In addition, the forensic pathologist identified blunt-force injuries on the head and face of the deceased, including an underlying nose fracture with detectable deformity, extensive bruising in the right lateral upper eyelid area, a laceration of the right upper lip and significant haemorrhages present in the inner aspect of the lower lip.
On the upper limbs in the area of the left upper arm and right upper arm, there were multiple graze abrasions and bruises inflicted prior to the death of the deceased. On the lower half of the body there were also extensive blunt force injuries constituted by bruising on the right leg - mainly in the upper region, and on the left leg – mainly in the lower region.
As well, there was bruising to the knuckles of the second and third finger of the deceased’s right hand, which were detected beneath the skin.
Dr Issabella Brouwer, the forensic pathologist called by the Crown, although she did not undertake the post-mortem examination herself, expressed her expert opinion that the direct cause of death of the deceased was “ligature strangulation in the context of blunt force head injury”.
Her evidence was that the blunt force head injury was a relevant factor in the death, but it could not be said to have been a contributing factor because there was insufficient evidence demonstrating that the blunt force head injury actually caused or contributed to the deceased’s death.
I accept Dr Brouwer’s opinion as to the direct cause of death and that the blunt force head injury was not a contributing factor to the death, noting that the opinion was not challenged by the accused, and there was no contradictory evidence.

Dr Brouwer agreed with senior counsel for the accused that, from what she had observed and noted in the material, the deceased did not suffer from any brain injury. She also agreed with senior counsel that the fracture of the deceased’s nose may have resulted in profuse bleeding.
The clothing of the deceased was removed at post-mortem and provided to the investigating police. The clothing was subject to further investigation which is referred to below.

Description of the Ligatures and Table Lamp

After each of the ligatures was removed from the body of the deceased in the course of the post-mortem examination, they were handed to police. The police carefully examined the ligatures and other items from the scene of the murder.
One of those items that was removed for examination was a pink table lamp, which consisted of a ceramic base and a pale pink lampshade. The cord, which connected the table lamp to the wall plug, was white. The cord had, I am satisfied, been separated into three pieces. It is not clear from the evidence that the separation of the white cord into three pieces occurred because the cord was actually cut by a knife, or scissors or some other tool, or whether the cord separated as a result of the significant force applied during the strangulation.
The first part of the white cord was that nearest the table lamp, down to a white switch located on the cord. It remained connected to the lamp. The far end, which connected into the wall plug, had been separated at a distance of what seems to be about 13cm from the plug.
The central and longest section of the white cord was the white ligature which measured, after removal at post-mortem, approximately 137cm in length. It was not knotted. It will be convenient to refer to this part of the white cord as “the white ligature”.
The other ligature, which was removed at the post-mortem examination, was a black extension cord, which measured 190cm in length. It will be convenient to refer to this cord as “the black ligature”. The black ligature was intact and had not been cut in any way. The plug and receptacle end remained attached to it. The ends of the black ligature were found at the back of the deceased’s neck.
Both the white and the black ligatures were subject to careful police examination, including the taking of swabs from various areas of the ligatures. The swabs were submitted for DNA examination and testing. The results are referred to below.

DNA Evidence

Police collected from the murder scene a significant number of swabs from what appeared to be blood on various items found at the scene, from furniture, walls and doors and also from the clothing and body of the deceased.
Those swabs were also submitted to the Forensic Biology/DNA Laboratory of the Forensic and Analytical Science Service (“FASS”) – a body under the control of NSW Health. An experienced scientist and employee at FASS, Ms Mhorag Campbell, gave expert evidence of her opinion about the DNA profiles obtained from the swabs taken from the crime scene, from the body of the deceased, and other items collected by police.
Ms Campbell set out her expert opinion about the DNA results in two Expert Certificates: the first dated 3 July 2025, and the second dated 16 July 2025. The evidence does not suggest that these DNA results were available at any time prior to these Certificates being completed and provided to police, the DPP and the accused.
Of the various DNA results which she obtained, Ms Campbell’s evidence, which I entirely accept and indeed the correctness of any of her expert conclusions was not challenged, included the following results of relevance.
A clipping of the deceased’s left fingernail, being Item number 1(c)(ii), was recorded as showing a positive screening test for blood, with DNA which was a mixture originating from two individuals. Neither the deceased nor the accused could be excluded as contributors to the mixture – the deceased being the major contributor and the accused the minor contributor. Of this sample, Ms Campbell said:

“Assuming there are two contributors and [the deceased] is one of those contributors, it is greater than 100 billion times more likely to obtain this mixed profile if it originates from [the deceased] and [the accused], rather than if it originates from [the deceased] and an unknown unrelated individual in the Australian population.”

Of the statistic of 100 billion, Ms Campbell said that when FASS is reporting on the identification of DNA profiles, 100 billion is the “… maximum or biggest number …” which is used. It will be convenient to refer to this component of her opinion involving the use of the figure of 100 billion, as being “the highest confidence assessment”.
Ms Campbell explained that the use of the phrase “an individual cannot be excluded as the source of DNA” means that when the scientists examine a DNA profile “… all of the components in that DNA profile match all of the components in an individual’s reference DNA profile”. Ms Campbell contrasted that description with where a person is excluded as the source of a DNA profile, namely “if at one or more of those areas [the profiles] don’t match”.
I am persuaded beyond reasonable doubt that the accused’s DNA was identified in this clipping of the deceased’s left fingernail because Ms Campbell’s opinion is expressed at the level of the highest confidence assessment, and because of the evidence of the surrounding circumstances.
Ms Campbell was asked about persistence of DNA on a fingernail or parts of the skin. She gave this evidence, which I accept:

“We know that DNA can persist for a long period of time on an item that’s stored in a cool, dark environment and untouched. It can persist on an item such as clothing for many years. An item such as a hand, it would be dependent on what happens after the DNA has been deposited. So, if an individual has DNA on their hands and then they’re fast asleep or they’re lying prone for a long period of time, the DNA can persist for a longer period of time. However, if they’re washing their hands or they’re using their hands to do lots of other jobs or touching other things, it’s possible that the DNA can be lost and it may be lost quite quickly, especially if washing has occurred.”

Further results were obtained from areas on the body of the deceased which were swabbed, being on the front (anterior) and the back (posterior) of the right hand/wrist/forearm, and on the anterior and posterior aspects of the left hand/wrist/forearm. In each case, the screening test for blood was positive. In each case, the DNA recovered from those areas of the deceased’s body was a mixture that originated from at least two individuals. In each case, neither the deceased, nor the accused, could be excluded as contributors to that mixture. In each case, the deceased being the greater contributor and the accused being the minor contributor. With respect to Item number 1(j), which was a swab from the back (posterior) aspect of the right hand/wrist/distal forearm, Ms Campbell’s opinion was at the level of the highest confidence assessment.
In her second Certificate, Ms Campbell made a similar confidence assessment and expressed a similar opinion with respect to Item 1(i), the right front (anterior) swab and the left back (posterior) swab which was Item 1(l). Of the left front (anterior) swab, which was Item 1(k), Ms Campbell gave a similar opinion, except that her level of confidence was expressed by the number 87 billion, which I regard as a very high number expressing a very high level of confidence, rather than 100 billion which is the maximum number used.
I am persuaded beyond reasonable doubt, having regard to each of the confidence assessments (even though they differed for one Item) in the context of all of the surrounding evidence, that the DNA discovered on these four swabs came from both the deceased and the accused and not from any other individual who has not been identified.
Two swabs were taken from the deceased’s vagina (Item 1(o)) and vulva (Item 1(q)). With respect to the vaginal swab, Ms Campbell reported as follows:

“Blood not detected.
Spermatozoa (sperm cells) not detected.
DNA testing was carried out using Y-STRs.
The partial male DNA profile recovered has the same Y-STR profile as [the accused] and is also expected to match all males on his paternal line.
It is greater than 2,300 times more likely to obtain this profile if it originates from [the accused] (or a paternal relative), rather than if it originates from an unknown, unrelated male individual in the general population.”

With respect to the swab of the vulva of the deceased, Ms Campbell reported as follows:

“A screening test for blood was positive.
Spermatozoa (sperm cells) not detected.
DNA testing was carried out using Y-STRs.
The partial male DNA profile recovered has the same Y-STR profile as [the accused] and is also expected to match all males on his paternal line.
It is greater than 2,600 times more likely to obtain this profile if it originates from [the accused] (or a paternal relative), rather than if it originates from an unknown, unrelated male individual in the general population.”

There was no evidence of the existence of any paternal relative of the accused except for his brother, Nathan. Whilst there is evidence that Nathan knew the deceased – he was the best man at her wedding – there is no evidence that Nathan had an intimate relationship with the deceased at any time, nor that he had been in her company at any time after the morning of Friday 13 January 2023. I am satisfied that Nathan can be entirely excluded as the contributor of these partial male DNA profiles. I note that neither the Crown nor the accused submitted that it was a possibility that Nathan was the source of these DNA profiles.
I accept these results, which satisfy me beyond a reasonable doubt that, although no semen was identified, the DNA of the accused was present inside the vaginal cavity of the deceased and on the deceased’s vulva, when her body was examined at the post-mortem examination.
On the exterior face of the deceased’s bedroom door in the unit, where there were a number of apparent blood spots and stains, and a possible fingerprint, investigators took a swab of that part of the scene and labelled that area “F1”. That swab was submitted to FASS and was reported on as follows:

“The DNA recovered is a mixture that originates from at least two individuals. [The deceased] cannot be excluded as the major contributor to this mixture. [The accused] cannot be excluded as the minor contributor to this mixture.”

Ms Campbell carried out statistical comparisons for this blood swab, which she recorded in her first Certificate. Those statistics were at the level of the highest confidence assessment. It is sufficient for me to note that, having regard to those statistics and the totality of the evidence, I am satisfied, beyond a reasonable doubt, that the DNA of each of the accused and the deceased was present in the swab taken from the bloodied area of F1 on the doorway into the bedroom.
Photographs of the exterior face of the door show that the area of F1, from which the blood swab was taken, was towards the bottom of the door, at a height which approximated the lower edge of the bottom hinge of the door, and was, I estimate, 5cm to 7cm from the floor.
It can be conveniently noted here that the fingerprint examination of the blood spots and stains in the area F1 on the exterior face of the door showed two palm prints of the right hand of the deceased.
The two extension cords which were found wrapped around the deceased’s neck were subjected to a number of swabs which were analysed. The black ligature was the subject of a DNA trace swab taken from an area near the plug which was given reference number R32 by FASS.
Dr Campbell reported that the DNA recovered from that area of the black ligature originated from at least two individuals. Neither the accused nor the deceased could be excluded as contributors to that mixture. Ms Campbell reported her opinion at the highest confidence assessment. I am satisfied beyond reasonable doubt that the DNA of the accused and of the deceased was found on the black extension cord near the plug end, which was retrieved at autopsy from around the neck of the deceased.
A number of swabs were taken from the white ligature, and the other two parts of what was previously a single white cord from the pink table lamp enabling it to be plugged into a wall socket. Each swab identified the DNA of the deceased as the major contributor with the highest confidence assessment. In each case but one, the minor contributor’s DNA was at too low a level to enable comparison with a reference sample.
In the case of one swab given reference number R52 by FASS, which came from the area marked as Item 2 shown in the photograph on page 1 of Exhibit 19, the item number of which was XF 000311262, according to a barcode visible in the photographs, DNA was identified from three individuals. The DNA profiles of the accused and the deceased were identified at the level of the highest confidence assessment. The DNA from the third contributor was at too low a level to enable comparison. I am satisfied beyond reasonable doubt that the DNA of the accused was present on that part of the lamp cord.
A number of tape-lifts were taken from the outside of the black trousers worn by the deceased at her work trial on the morning of 16 January 2023, and which she was still wearing when she was found. The tape‑lifts were taken from two areas of the rear of both the right and left calf of the trousers. The areas from which the swabs were taken are outlined in yellow in the photo on page 4 of Exhibit 19.
Ms Campbell reported, with respect to those four tape‑lifts, that the DNA recovered was of at least two individuals and that, in each case, neither the deceased, nor the accused, could be excluded as contributors to that mixed sample. In respect of each of these tape‑lift samples, Ms Campbell reported her opinion at the highest confidence assessment level, that the DNA profiles were of the deceased and the accused.
I am satisfied beyond reasonable doubt that the DNA of the accused was found on the rear of the right and left calf area and in the below‑knee area of the black trousers worn by the deceased.
I am also satisfied beyond reasonable doubt that the DNA of the deceased and the accused was identified and could not be excluded from the following locations on the clothing being worn by the deceased at the time of her death:

a tape‑lift from the left side of the deceased’s underwear, being the area ordinarily located around the deceased’s waist;

a tape‑lift of the interior of the right side of the waist area of the black trousers being worn by the deceased;

a swab of the zipper and button of the black trousers being worn by the deceased;

three tape‑lifts taken from the front of the shirt worn by the deceased at the time of her murder; and

a tape‑lift taken from the exterior of the right cup of the bra which the deceased was wearing when she died.

In respect of the DNA of the accused found in the items just listed, Ms Campbell has reported her opinion about the presence of the DNA of the accused with the highest confidence assessment. This confidence level, taken with the other evidence, leads to my conclusion beyond reasonable doubt about the presence of the accused’s DNA on those areas.
Some other parts of Ms Campbell’s evidence need to be referred to. To some extent, the evidence included matters of common sense. In her evidence, Ms Campbell was asked, by way of summary, about the DNA of the accused at the crime scene. She gave the following evidence:

“Q. … as I understand it, Paul Sultana’s DNA could not be excluded from the swab of the white cord that was found on the bed, four different areas of the back lower half of the deceased’s pants, the right side of her underpants, the right side of the waistband of her pants, the zipper and buttons of her pants, three different swabs from the front of her shirt, the swab of her right bra cup, a swab of the end of the black extension lead, both sides of her left wrist, both sides of her right wrist, her vagina and her vulva, and was also under one of the fingernails on her left hand?
A. I think I was following that correctly. Yes.”

This seems to be a useful and correct summary of the results of DNA profiles identified at the scene of the murder. The widespread presence of the accused’s DNA on the deceased’s body, on her clothing, on each of the black ligature and a part of the white cord, under her fingernail and in the blood on the exterior face of the bedroom door, provides a significant part of the Crown case against the accused for the murder.
In cross-examination, Ms Campbell agreed that DNA could be transferred from a surface upon which it has first been deposited onto another surface. She agreed that it would be possible, in the normal course of people living in a domestic relationship for some time, for DNA to be deposited in multiple places inside the house.
With respect to DNA being transmitted in the course of a sexual relationship, Ms Campbell was asked this question and gave this answer:

“Q. … In this case, if you assume a sexual relationship involving normal heterosexual intercourse, that could leave traces of DNA inside the vagina or on the vulva, correct?
A. Yes, that’s possible. … if a condom was worn, then there’s potentially less chance for transfer of DNA from a penis to the internal vagina or the external areas, but there may be other aspects of sexual contact that may lead to DNA transfer.”

Further, with respect to the swabs from the accused’s vagina and vulva, Ms Campbell gave this evidence:

“Q.   … so far as a comparison between the vagina and the vulva was concerned, it would be, in your opinion, likely that DNA would be better retained in the vagina for a longer period than on the vulva. Is that correct?
A.   Yes, because the vaginal cavity is an internal cavity. It’s more protected from external influences such as rubbing of fabric from clothing or from washing.
Q.   It could be retained inside the vagina for up to 72 hours, I think you said?
A.   Yes. So, when we’re looking at potentially trying to locate foreign DNA … the research indicates that it can generally be picked up if there was deposition within the first 24 to 48 hours, possibly up to 72 hours, but that’s much less likely than within the first 24 hours. That’s talking about skin cells. It’s possible if there are very small traces of sperm cells – we know sperm cells can persist up to five days, but in this instance, we didn’t detect any sperm cells.”

With respect to persistence of DNA, Ms Campbell, in re-examination, said that, whilst DNA can persist through showering “… common sense would dictate that potentially things are lost more frequently through swimming and showering”, although there was no specific research available on that matter.
Ms Campbell agreed that, merely by looking at a DNA profile, scientists such as herself could not tell how or when that DNA was deposited on the surface which had been swabbed, or else from which a tape‑lift had been taken.

Evidence of Ms Kelly Ryan

Ms Ryan was the person who, as the neighbour of the deceased, heard a variety of noises and made observations at about the time the deceased was killed. Her evidence provides the only contemporaneous independent witness account surrounding the period of the death of the deceased. As such, it is evidence which is central to the Crown’s case that the accused murdered the deceased. It is now appropriate to discuss that evidence in greater detail and to enable a later consideration of, in light of the directions which apply to it, whether I accept it.
Ms Ryan lived in Unit 18 of the unit complex. Her unit was across the corridor from the deceased’s unit. Their front doors were directly opposite each other.

“Q. But you turned your phone off, Mr Sultana, at about 9.30 in the morning?
A. My phone was dying.”

He repeated that answer in the following question and answer.

Later in his cross-examination, he gave this evidence:

“Q. You then rode back to Dayna’s house, arriving at about 9.30, and switched off your phone. Correct?
A. Switched off my phone, correct.”

Later in the cross-examination, he was asked this question and gave this answer:

“Q. At the time of that murder, your phone was switched off. Correct?
A. Yep.”

I do not accept that the reason the accused’s telephone was not connected to the network via various cell towers, for a period of 4½ hours, was because its charge had run out, and it was necessary for the phone to be recharged. That is simply an explanation which I cannot accept. If the phone had died, and needed recharging, there was no need to, and it would be illogical to, turn it off. If the charge had expired first, it could not have been turned off. Once connected to a recharge source, which the accused said was the case, a mobile phone does not need to be fully charged – a process which may take a period of some hours – before it connects back to a network. A mobile telephone can be connected to a network with only a small amount of charge existing. Given the accused’s use of his phone, which seems to be regular, even if the phone had been turned off just prior to running out of power, it is in my view unlikely that the accused would not have accessed the phone as soon as it had power sufficient for him to reconnect to the network. In other words, it is against all probability that the accused would have left the phone switched off, even though there was adequate power to enable him to reconnect to the network unless he deliberately did not wish to be contacted, or for his whereabouts to be traced through the connection with various cell towers.
It is also relevant to my conclusion that, when reconnected to the network, the accused had already left the scene of the killing at the deceased’s unit. He was some kilometres away, and about half an hour had elapsed since he left the deceased’s unit, before he turned his telephone back on. In other words, I conclude that he had decided to make sure that his phone was not able to be traced to the vicinity of the deceased’s unit during the time that the deceased was killed and that he only switched it back on when it could not be said that he was in the vicinity of the deceased’s unit.
In my opinion, the accused deliberately switched his telephone off and left it switched off until approximately 2.00pm, so that he would not leave any trace of his location being at, or else in the near vicinity of, the deceased’s unit, so as to avoid being implicated in the death of the deceased. I do not accept his evidence which is to the contrary of this conclusion.

Purpose for Bringing the Rope and Tape to the Deceased’s Unit

The accused gave an explanation that he attended at the deceased’s unit with the rope and box-tape for the purpose of tidying up and putting away the Christmas tree and decorations that were in the unit. The accused first gave this account in the course of his evidence. He had not given it to the police in the course of his Recorded Interview. I do not accept the accused’s evidence that that was the purpose of his visit to the deceased’s unit, nor his explanation as to why he took the rope or box tape. I have earlier at [426]-[427] set out my reasons for rejecting this account of the accused.
I am well satisfied that the accused’s sworn evidence as to this purpose was invented by him to account for the fact that he had been filmed taking rope and a roll of box-tape on his bicycle when he went towards the deceased’s unit on the morning of the Monday. It is most unlikely that, at the time of his police interview, the accused realised that there would be recoverable CCTV footage showing him carrying rope and box-tape when he cycled to the vicinity of the deceased’s unit.
Further, as earlier noted, it was the type of domestic task which was entirely inconsistent with the state of the relationship between the accused and the deceased on that morning.

Other Parts of the Accused’s Evidence

There are a number of other parts of the evidence of the accused which I do not accept, which combined with those matters to which I have already referred, lead me to the conclusion with respect to the evidence of the accused that, unless something the accused said was independently corroborated by reliable evidence, or that it was an admission against his own interest, the evidence simply cannot be believed or accepted. It is, in my judgment, not possible that it might be true.
The further matters are:

In light of my acceptance of Ms Ryan’s evidence as to what she heard, and my conclusion that the accused did not have any keys to the deceased’s unit enabling him to freely enter the unit when he chose, prior to her murder, the accused’s evidence as to falling asleep on the couch in the deceased’s unit until he was woken by “an awful bang … [which] sounded … like a bomb went off …” is untrue. If there was such a noise sufficient to wake the accused from a slumber deep enough so that he did not hear the sounds and noises of any physical assault on the deceased, including a very loud scream, it must have been heard by Ms Ryan. But she heard no such sound. This is because, I am satisfied, that there was no such noise and the evidence of the accused saying so is untrue.

The accused had seen the deceased lying on the bed in her bedroom when he left the unit on the Monday afternoon: he said “I seen her laying there”. When he returned to the deceased’s unit with his mother, the deceased was still lying on the bed in the same position – no one had been in the unit between the two visits. He knew that the deceased was in the same place and state because he could see her, and because of the remarks made to him by his mother, including the words asking what he had done and telling him that she could not fix it. Yet, later that afternoon, in the phone calls and in the text messages described earlier, the accused pretended that he had not seen the deceased on the Monday, and did not know where she was, or what had happened to her. Yet, in his evidence in the trial, the accused said:

“Q.   Now, during the course of the day –
A.   Yep.
Q.   - there was contact between yourself and several people in which you implied that you didn’t know what had happened to Dayna?
A.   Yep.
Q.   Why did you do that?
A.   Because I didn’t know what happened to her.
Q.   Well –
A.   I knew, I knew where she was … and I knew that she wasn’t well.” (emphasis added)

In the answer, which is emphasised, the accused maintained his earlier pretence about his lack of knowledge of the deceased’s well-being and continued to falsely suggest that he was in ignorance of the deceased’s well-being, which he was not, because he had seen her twice on the Monday afternoon. A truthful answer in this Court would have been for the accused to have admitted the fact of his untrue pretence on the Monday, but he did not do so.

As earlier noted, a text message was sent on the Monday at 3.56pm from the accused’s phone, addressed to the deceased. It contained the pretence that the accused did not know that the deceased was dead. He was sending a text which reflects, on its face, a not unusual message in the course of an ongoing relationship which was consistent with earlier text communications. The evidence was that such a message was downloaded from the accused’s phone through the Cellebrite process. In evidence, the accused denied that this message came from his phone. But it is beyond doubt that it did so, his phone was in his possession at that time, no one else had access to it, and the nature and content of the message only makes sense if it was sent by the accused to maintain the appearance of an ongoing relationship and that so far as the accused was concerned, he did not know that the deceased was dead. The accused’s evidence at trial was false.

Ultimately, in evidence, the accused was compelled, in cross-examination, to advance an explanation for the prosecution case in this way:

“Q.   So is it your position, Mr Sultana, that everybody – Ms Ryan, the police, me, the DNA expert – are all making up evidence to make you look guilty?
A.   Yep.
Q.   Do you have any thoughts on why we would do that?
A.   You need someone to close the case on, don’t you.”

This patently absurd answer was ultimately the only way that the accused could articulate a response to the Crown case. I am satisfied beyond reasonable doubt that the evidence of Ms Ryan, the investigating police, and Ms Campbell, the FASS scientist, was not made up at all, and certainly not made up for the purpose of closing the case by falsely implicating the accused.
Just as the accused intentionally gave a false account of the events surrounding the death of the deceased to the police in the course of the Recorded Interview in order to distance himself from being implicated in her death, so too I am satisfied that he has done so whilst giving evidence at this trial. His version of events by which he exculpates himself and seeks to blame an unknown third-party for the deceased’s death is simply not true. There is no possibility at all that his version of events might be true.
It is clear from my earlier analysis of the evidence that the killing of the deceased is likely to have occurred over a period of 10 minutes or so – that is a short period of time. I have found that there were no signs of any forced entry into the deceased’s unit. There was no damage to the front door of the unit, and the lock was intact when Ms Ryan heard the accused first leaving the unit. When police officers first visited the unit, there were no visible signs of any disruption to the possible entry point from the patio into the unit. In other words, if an intruder had entered through the window as Senior Constable Hayward did, then the intruder must have closed the window and ensured that the air-conditioning duct remained in, or was replaced to, its ordinary position, before attacking the deceased.
The evidence did not reveal that anyone other than the accused (and the deceased) had entered or left the deceased’s unit. In other words, having regard to the evidence, there was no intruder seen or heard entering or leaving the deceased’s unit. The evidence did not identify any person who may have had a motive to kill the deceased, including Mr Mikkel Isaac. He had no motive to cause the death of the deceased, who was the primary carer for his two young children. The evidence did not provide any facts which could ground a conclusion that an unidentified assailant had entered the deceased’s unit for a criminal purpose, such as robbery, whose criminal enterprise was discovered or interrupted when the deceased came upon it, or for the purpose of assaulting the deceased.
No DNA profile was developed from any of the swabs taken at the crime scene, and from the deceased or her clothing, which identified any other individual, either male or female. The fact that the swab given reference number R32 by FASS (referred to above at [196]), identified a third contributor, does not support a reasonable possibility that it alone, in the absence of any other DNA of a third person, and in the presence of the widespread occurrence of the DNA of the accused, suggests that the deceased was murdered by an unidentified third‑party assailant.
For all these reasons, I do not believe that the evidence of the accused was truthful, and I do not accept it as truthful and reliable unless it is corroborated by reliable evidence, or else is a statement made against his interest.

Does the Evidence Establish that the Accused was Intoxicated at the Relevant Time?

Senior counsel submitted that it was, having regard to the evidence, necessary for the Court to consider whether the accused was under the effect of self‑administered drugs and alcohol to such an extent that at the time of the deceased’s death, he was incapable of forming any subjective intention of the kind necessary to constitute the offence of murder.
It is convenient, here, to identify and consider the evidence of, or else which may be relevant to, the self‑intoxication of the accused, and the extent to which he was affected.
Senior counsel for the accused draws attention to various parts of the transcript of the accused’s evidence, to a number of answers given by the accused in the course of the Recorded Interview, and to the general demeanour and appearance of the accused during that interview. He also draws attention to the demeanour of the accused, which can be observed in a number of video clips which were filmed after the accused returned to the Cranebrook property, having destroyed the RAV4 by setting it alight.
Whilst evidence about what the accused looked like, what he said and what he did after the death of the deceased may have possible relevance, the weight to be given to it will necessarily diminish as the time from the act of killing the deceased passes. That is because the essential question is what the state of the accused’s intoxication was at the time of the deceased’s death. Any later state of intoxication may be affected by a number of factors that were not present at the earlier relevant time, including taking further drugs and drinking more alcohol.
For the purposes of this analysis, I have taken the evidence of the accused at its highest, even though, as earlier explained, I do not accept the accused as a witness of truth.
The accused in his evidence-in-chief did not give any evidence about taking drugs or drinking alcohol in the 24-hour period leading up to the death of the accused. Nor did he give any evidence either at all, or to any described extent, about being intoxicated at any time whilst he was in the deceased’s unit prior to her being killed. He did not say that he was intoxicated or felt in any way deprived of the capacity to be capable of forming any specific intention. In fact, the accused’s stated purpose of going to the deceased’s unit with the specific intention of packing up Christmas decorations suggests that he was capable of clear thought and acting with purpose.
I record this, not because the accused has any onus to prove that he was intoxicated or felt incapable of forming any specific intention at the relevant time, but rather to note that the principal primary source of the state and effect of the accused’s self-intoxication at the relevant time said nothing about being intoxicated.
In the course of cross-examination on the topic of what the accused had heard when, on his evidence, he had fallen asleep on the couch, the accused said that, on the evening before the deceased’s death, he had taken Valium and Xanax “… because I was running around all night …”. He agreed that these drugs were sedatives but would “backwash … For me, downers are uppers”. No question was asked in cross-examination about the quantity of drugs consumed, nor was there any evidence given about the extent of his self-intoxication on the Monday prior to or at the time of the deceased’s death.
In re-examination, the accused said that he had been buying and selling drugs during the evening of the Sunday and in the early hours of the morning of the Monday.
The accused gave this evidence in answer to a question as to whether he had been outside the deceased’s unit during the night:

“A. I wasn’t. I was in fact dispersing drugs throughout the area.

His evidence continued:

“Q. All right, and using some yourself?
A. Yeah.”

There was no other reference to any quantity, or amount, of drugs consumed at the relevant time.
In the course of the Recorded Interview, in the context of what is now admitted to be a false statement, the accused said that he had no memory of, and no knowledge of, what he did on Monday 16 January. In the context of that statement, he told police that his memory loss was explained by him taking drugs. The following exchange then took place:

“Q.177   OK. So Monday morning, I take it, did you take a number of drugs?
A.   Yep.
Q.178   And how many are we talking?
A.   I couldn’t tell you.
Q.179   Have you ever done this before?
A.   What?
Q.180   What, you take drugs and you don’t remember anything?
A.   No.
Q.181   You’ve never done that before?
A.   No.”

Later on in the Recorded Interview, the accused was asked whether he had anything to drink on the Monday. He said that he had drunk Jack Daniels, or Gentleman Jack. The accused did not know if that was scotch or bourbon. He was asked about the quantity consumed:

“Q.318 … So, in that period between Sunday, just say through to when you were arrested, can you tell me how much you had to drink?
A. I don’t know how much I drink (sic). I drink it straight from the bottle.”

The accused said that, on the Monday, he was completely blind when he was at home through a combination of Gentleman Jack and drugs. He also said that, after he returned home from his bicycle ride, he resumed drinking for hours.
I have already noted that these statements by the accused to the police were not true and so are not probative of any state of self-intoxication. But even if I was to accept that these statements were true, they would not assist in the proof of the extent of self-intoxication at the time the deceased was killed.
There was other evidence which casts light on the extent, if any, of the accused’s possible self-intoxication. This evidence includes the CCTV evidence of the accused’s movements in and around the Cranebrook property between about 11.52pm on the Sunday, when the accused rides away from the property on a motorbike, having first put on a vest with some high-visibility reflectors and a safety helmet, in an entirely rational manner and generally behaving without difficulty, up until about 9.02am when the accused rides away from the Cranebrook property on a bicycle and navigates his way over the next 25 minutes or so towards the deceased’s unit.
During this 9-hour period, the accused is able to:

upon returning to the Cranebrook property, dismount from the motorcycle and manoeuvre it, without difficulty, through a tight space into the undercover carport area;

open and close a large side-gate to the property and wheel a bicycle outside to the grass verge without any difficulty;

having returned inside the house at the Cranebrook property, to leave it by walking out of the front door, descending some steps having closed the front screen door quietly, without any stumbling or apparent lack of co-ordination;

some hours later, shortly before 9am, riding his bicycle in a normal way, then leaving it on the grass verge and scaling a fence or gate, which is about 2m high, to access the backyard of the Cranebrook property. This manoeuvre requires balance, dexterity and care, and is accomplished with ease by the accused;

searching at the Cranebrook property for two items, rope and box tape, and then climbing back out of the property over the same fence or gate with ease, including a jump down to the ground of about 1m;

attaching an item or items to the bicycle before setting off to ride to the deceased’s unit; and

making his way for a period of about 25 minutes whilst riding his bicycle quite conventionally, demonstrating good balance and the capacity to turn corners and navigating purposefully towards the location of the deceased’s unit.

My observation of the behaviour of the accused captured over the period just described enables me to conclude that there were no visible or external indicia of any impediment arising from self-intoxication of drugs or alcohol affecting, to the slightest, the capacity of the accused to do all of the things described.
It is certainly not the case that, on the Sunday evening and up until about 9.30am on the Monday morning, the accused was so affected by self‑intoxication of drugs and alcohol that he was unable to form any specific intention to do any act that he chose so to do. His movements were all purposeful. He knew what he was doing.

Nothing is revealed by the evidence as to what the accused did between 9.30am or so and around 1.10pm or so, which would account for any change in the state of intoxication of the accused. To the extent that his evidence had any credibility, the accused did not suggest that he took any drugs or drank any alcohol after he let himself into the deceased’s unit.
The observation of Ms Ryan of the accused as he left the deceased’s unit and walked down to the underground carpark is inconsistent with the accused being intoxicated to such a degree that he was incapable of forming any specific intention.
On his own evidence, the accused was capable of, and did form, the specific intention of taking the RAV4, including first taking the deceased’s keys, and remembering to collect his phone and charger, and other belongings, and driving quickly, although in a conventional manner, on the correct side of the road, to get away from the unit complex.
I reject the accused’s submission that I could find, on the evidence, that at the time of the death of the deceased, he was so intoxicated by the taking of drugs or the drinking of alcohol that he was incapable of forming an intention to kill the deceased, or to cause grievous bodily harm. He was not incapable of having the subjective foresight necessary to constitute reckless indifference to human life.
Shortly put, there is no credible evidence that the accused was intoxicated to such an extent, and all other evidence leading up to and immediately after the killing of the deceased, positively persuades me that he was not so intoxicated. It follows that on the evidence, I am satisfied beyond reasonable doubt that the accused was capable of forming a specific intention to kill or cause grievous bodily harm.

Has the Crown Proved that the Accused Killed the Deceased?

I am satisfied beyond reasonable doubt that the Crown has proved that the accused killed the deceased.
I have set out above my discernment leading to this conclusion. However, it is convenient to provide a summary of my conclusion in a somewhat different sequence.
I have put to one side, and not taken into account, any evidence in the trial, or the version given to police in a Recorded Interview, which came from the accused. That is because the accused himself has disavowed the truth of his police interview, and I have disbelieved his evidence, unless it is corroborated by independent reliable evidence or else amounts to an admission against his interest.
The killing of the deceased occurred against the background of an unsettled relationship in which the accused was showing feelings of jealousy and was unable to accept a relationship of the kind which the deceased wanted. These were conflicts in the relationship existing at the time of the deceased’s death.
At about 9.00am, when the accused set off to cycle towards the deceased’s unit, he was clearly aware that the deceased had gone to a trial of the work with a prospective employer. He took with him rope and box tape.
The accused deliberately turned off his mobile phone at about 9.30am and did not switch it back on until a little after 2.00pm. He did so in order to avoid being detected as being in the vicinity of the deceased’s unit when she was killed.
On his own evidence, the accused was present in the deceased’s unit when she was killed, he left shortly afterwards in the deceased’s RAV4, later returned to the unit with his mother, and ultimately destroyed the deceased’s vehicle by burning it.
The evidence of Ms Ryan identifies the only male voice coming from the deceased’s unit during the violent physical assault which took place over a relatively short period as being that of the accused and whom she also identified visually when leaving the unit.
The DNA of the accused was found and identified to a high level of certainty in a significant number of locations which show that the accused must have been involved in the killing of the deceased: namely, on the black ligature used to strangle the deceased and on a part of the white cord; amongst the blood spatters on the door to the deceased’s bedroom, on a shirt, bra, trousers and underpants which the deceased was wearing when she was killed; on her body; in and on her genitals; and under her fingernail. The presence of DNA cannot be explained by any transfer occurring during ordinary domestic activities or any form of domestic cohabitation.
There is no evidence to support, as even a remote possibility, let alone a reasonable one, the presence of an unidentified male in the deceased’s apartment at the relevant time, who was responsible for killing the deceased. In fact, the evidence is to the contrary of there being a third-party intruder.
The accused’s conduct after the death of the deceased is consistent only with his being the person responsible for the death of the deceased. He fled the scene rather than calling the police or ambulance; he stole and destroyed the deceased’s RAV4 which he had been driving around to avoid being implicated; he sent out a false text message to the phone of the deceased and to the deceased’s father; and he told lies to the deceased’s father and to police in a Recorded Interview about his whereabouts, knowledge of the death of the deceased and his involvement. He did so for the sole purpose of seeking to avoid being implicated in the death of the deceased.
All of these matters lead inexorably to my conclusion, of which I am satisfied beyond reasonable doubt, that the accused deliberately killed the deceased by strangulation.
It follows that, notwithstanding the comprehensive submissions of senior counsel for the accused urging me to find that the Crown had not proved that the accused killed the deceased, I am satisfied beyond reasonable doubt that he did so.
It is necessary now to consider whether the Crown has satisfied me, beyond reasonable doubt, that at the time the accused deliberately killed the deceased, he had the specific intention necessary for his conduct to amount to murder.

Has the Crown Proved that the Accused Intended to Kill the Deceased?

Murder is an offence which requires proof beyond reasonable doubt of a specific intention – either to kill or cause grievous bodily harm, or else to act with reckless indifference to human life, which requires subjective forethought of the probability of death from that act.
Whilst the accused agrees that, if his level of intoxication with drugs or alcohol, or both, were such that he was incapable of forming either of the necessary intentions, or being recklessly indifferent to human life, he would be guilty of manslaughter, having regard to my factual conclusions expressed at [474]-[479] above, the issue of the alternative verdict of manslaughter does not arise.
The specific intention (or acting reckless indifference) must be proved beyond reasonable doubt by the Crown. The accused does not carry any onus with respect to the disproof of such specific intention.
Murder is defined as an offence of specific intent: s 428B Crimes Act 1900 (NSW) (“Crimes Act”). Evidence of self-induced intoxication, at the time of the relevant conduct constituting the offence, may be taken into account in deciding whether the accused had the requisite intention: s 428C Crimes Act.
After a review of the evidence about the extent of the accused’s self‑intoxication, I have earlier concluded that there is no credible evidence that the accused was so intoxicated that he could not form a specific intention to kill or cause grievous bodily harm to the deceased.
Put differently, I am positively satisfied that the accused was capable of forming the intention necessary for a conviction of murder. This issue now being considered is whether the Crown has proved that he had formed such an intention.
My analysis from the facts proved about how the accused killed the deceased – i.e., the infliction of the blunt force trauma injuries, followed by the deceased being dragged (or forcibly moved) onto the bed, the use of two ligatures wrapped tightly around the deceased’s neck, who was then deliberately strangled by the use of considerable force, at a time when the deceased was vocally and physically resisting the accused, compels me to reach the only conclusion available, which is that the accused intended to kill the deceased when he strangled her.
If the intention of the accused was only to seriously injure the deceased, he achieved that intention prior to the strangulation. The use of two ligatures, wound tightly three times around the deceased’s neck, clearly demonstrates that the intention of the accused was to kill the deceased.
I am satisfied beyond reasonable doubt that, having regard to all of the evidence, including the acts of the accused by which he first assaulted and then strangled the deceased, that he had the specific intention to kill the deceased, and acted upon that intention whilst he strangled her.

Assessment of Person A’s Evidence

Although it is not necessary for my conclusion that the accused killed the deceased, it is nevertheless appropriate to consider whether I accept the evidence of Person A, and if so, to what extent and what weight can be given to it.
When describing Person A’s evidence, at [260], I reminded myself that I needed to exercise caution when considering whether to accept Person A’s evidence. I set out the reasons why caution should be exercised, including that the evidence of Person A may simply be unreliable.
In considering whether or not to accept the evidence of Person A, I need to consider all of the other evidence in the trial, and keep in mind that he is not describing any matter or fact about the death of the deceased, about which he has no direct knowledge. Rather, Person A’s evidence is what he was told by the accused about the deceased’s death and surrounding circumstances.
In considering whether to accept the evidence, I note the following features:

Person A accepted that he was giving evidence whilst, in part, motivated to obtain an advantage for himself when coming to be sentenced for a number of firearm offences;

he made handwritten notes of the contents of his conversations with the accused, which notes he gave to police, and which have been disclosed to the accused;

some of the conversations about which he gave evidence contained “unpublicised” details about the deceased’s death, as I have earlier noted at [273], [275], [278] and [282]; and

the contents of some of the conversations are consistent with the evidence of a number of witnesses, including Ms Ryan and Ms Campbell, about whose evidence Person A could not have known.

I closely observed the demeanour of Person A whilst he was giving evidence. There was nothing about his demeanour which enabled me to conclude whether he was telling the truth or not.
On balance, I accept that the accused made admissions to Person A, generally, in accordance with what Person A said, as recounted in [273], [275], [278] and [282]. The contents of these conversations were such that only the person responsible for killing the deceased could have known of each of them, and the totality of them. I note that Ms Tsiliris may have made observations of the scene, but it is not suggested that her observations were the source of Person A’s knowledge.
My acceptance of the identified parts of the evidence of Person A also relies on the fact that the evidence did not identify any possible source or pathway for the provision of information to Person A, except for the accused. For example, there was no co-accused in custody who could have provided such details. Person A had no access to any external media or news reports containing any detail of the death of the deceased. The accused was the only source of information about the death of the accused.
Accordingly, whilst it is unnecessary for me to base my conclusion about the accused being the person who killed the deceased upon the evidence of Person A, and I do not do so, nevertheless, I record that part of Person A’s evidence, which is contained in the identified paragraphs, is consistent with, and supportive of, my conclusion.
I do not need to engage in a consideration of whether other parts of the evidence of Person A should be accepted or taken into account. Whatever that evidence was, it does not cause me to doubt the accuracy of Person A’s evidence with respect to the material in the identified paragraphs.

Tendency and Coincidence Evidence

The Crown tendered evidence to establish a tendency, on the part of the accused, to act in a particular way, namely:

“To use violence or the threat of violence towards women in whom he has a sexual interest when he perceives that his relationship with them is breaking down.”

The Crown also relied upon the evidence for a coincidence purpose – namely, having regard to the evidence of the previous unlawful conduct, the killing of the deceased was not to be innocently explained as a coincidence.
The Crown tendered either Agreed Facts or else Crown Statements of Facts involving offences committed by the accused, with respect to Ms Cassie Gardiner, Ms Rebecca Swan and Ms Renee Millar.
The conduct of the accused towards Ms Gardiner occurred in 2011 and involved a forcible kidnapping by the accused of Ms Gardiner, forcing her into the back seat of a vehicle, and directing the driver where to go whilst shouting at the victim about their relationship. The accused prevented Ms Gardiner from leaving the vehicle. The accused was heard by police, when they arrived, repeating to the victim, “Babe, I love you. I love you. I just want to talk to you”.
The conduct involving Ms Swan occurred after the accused and Ms Swan had been an intimate relationship for about nine months. Early in the morning of 27 December 2012, about six months after the accused and Ms Swan had terminated their relationship, the accused broke into Ms Swan’s premises and entered her bedroom. An argument ensued, in which it became apparent to Ms Swan that the accused had a blue-handled knife in his pocket. Some hours later, Ms Swan awoke to the accused shouting at her about messages that had been found in her phone and condoms that were in her bedside drawer. The accused physically attacked her and squeezed her throat. He forced her to the ground saying, “I should just kill you”.
The third witness, Ms Millar, was in a relationship with the accused in 2016, after her then partner entered custody for a matter which did not relate to Ms Millar. The accused and Ms Millar developed a relationship which involved the accused staying at her home from time to time. At a time after Ms Millar’s partner had been released from custody, an incident occurred in which the accused, using his vehicle, having pulled up in front of the vehicle in which Ms Millar was a passenger, put his car into reverse and “rammed” and “smashed” his vehicle into the vehicle in which Ms Millar was a passenger. He did so a number of times on that occasion. He then chased Ms Millar’s partner through a paddock with his vehicle.
The facts shortly recited, which, as I have said, were unchallenged, establish a tendency on the part of the accused to resort to violence in order to engage in, or continue with, a relationship when he desired to do so, in circumstances where his partner did not share such a desire.
I have come to the conclusions which I have, with respect to the guilt of the accused, without reference to, or any reliance upon, this tendency and coincidence evidence.
In my view, having regard to the time at which the conduct relied upon occurred, namely at least 7 years, and up to 11 years, before the offence here, and the difference in the nature of the offences, no weight can be placed upon the evidence for either tendency or coincidence purposes, and I do not do so. Whilst I have not given any weight to the established tendency as a circumstance supporting the guilt of the accused, I do note that it is not a circumstance which provides any support for the accused’s denial of his involvement.

Conclusion

On analysis of the facts proved by the Crown, I have been satisfied beyond reasonable doubt that the accused deliberately physicallyl assaulted and then strangled the deceased, thereby causing her death.
The Crown has proved beyond reasonable doubt that there was no unidentified third party intruder in the deceased’s unit who murdered the deceased whilst the accused was present but asleep.
The Crown has proved beyond reasonable doubt that the accused was not so affected by self‑intoxication of drugs or alcohol that he was incapable for forming any specific intention to kill or cause grievous bodily harm to the deceased.
For all of these reasons, I have been satisfied beyond reasonable doubt that the accused is guilty of the offence of murder, as charged.
I enter the following conviction:

Paul Jason Sultana, you are hereby convicted of the offence of the murder of Dayna Isaac on 16 January 2023, at Penrith, in the State of New South Wales.

**********

Amendments

29 September 2025 - Typographical error on coversheet

02 October 2025 - Amend paragraphs 257, 263 and 268 to align with suppression orders.

Decision last updated: 02 October 2025

Medium Neutral Citation:	R v Sultana (No.7) [2025] NSWSC 1102
Hearing dates:	09 July 2025
Date of orders:	14 July 2025 – 18 July 2025; 21 July 2025, 22 July 2025, 24 July 2025.
Decision date:	26 September 2025
Jurisdiction:	Common Law
Before:	Garling J
Decision:	Guilty of the murder of Dayna Isaac
Catchwords:	CRIMINAL LAW – Murder – Single count of murder – Trial by Judge alone – Circumstantial case – Plea of not guilty – Strangulation by two ligatures – Sexual intercourse with body after death – Crime scene evidence – Evidence of a struggle – Whether alternative verdict of manslaughter made out – Mental element – Specific intent – Effect of intoxication – Case for the accused – Third-party intruder theory – No evidence of a break-in – Where the accused’s post-offence conduct was said to be the result of a panic that he would be blamed for the murder CRIMINAL LAW – Witness evidence – Expert evidence – DNA evidence – Where a witness being the next-door neighbour of the deceased was able to provide a contemporaneous account of the murder – Where the accused was positively identified by a witness as leaving the scene of the murder immediately after the murder occurred CRIMINAL LAW – Witness evidence – Pseudonym order – Where an informant has given evidence to the Court of admissions made by the accused whilst incarcerated – Where information provided to the Court by an informant could only have come from the murderer – Prison informer CRIMINAL LAW – Post-offence conduct – Where the accused’s post-offence conduct demonstrated a consciousness of guilt – Where the accused brought his mother to the deceased’s body – Where the accused drove the deceased’s vehicle to a remote area and set it on fire – Where the accused burnt his clothes following the murder – Where the accused changed his appearance following the murder – Where the accused demonstrated suicidal ideations following the murder
Legislation Cited:	Criminal Procedure Act 1986 (NSW) ss 132(1), 133 Evidence Act 1995 (NSW) s 184 Crimes Act 1900 (NSW) ss 428B, 428C, 428E(1)
Cases Cited:	Shepherd v The Queen [1990] HCA 56; (1990) 170 CLR 573 Liberato v The Queen [1995] HCA 66; (1985) 159 CLR 507
Texts Cited:	Not Applicable
Category:	Procedural rulings
Parties:	The Crown Paul Jason Sultana (Accused)
Representation:	Counsel: Y Prowse (Crown) Dr G Woods KC (Accused) Solicitors: Director of Public Prosecutions (Crown) Proctor & Associates (Accused)
File Number(s):	2023/17108
Publication restriction:	Not Applicable