R v Matthews-Boysen - [2025] SADC 30

DISTRICT COURT OF SOUTH AUSTRALIA
(Criminal)
R v MATTHEWS-BOYSEN
[2025] SADC 30
Reasons for Ruling of his Honour Judge Handshin
31 March 2025
CRIMINAL LAW - PROCEDURE - WARRANTS, ARREST, SEARCH, SEIZURE AND INCIDENTAL POWERS - SEARCH AND SEIZURE CRIMINAL LAW - EVIDENCE - JUDICIAL DISCRETION TO ADMIT OR EXCLUDE EVIDENCE - POLICE INTERROGATION - PROPRIETY OF POLICE QUESTIONING AND OTHER CONDUCT BY POLICE - ADMINISTERING CAUTION - PARTICULAR CASES
The applicant is charged with one count of trafficking a commercial quantity of a controlled drug. The charge arises out of a search of a property at Mitchell Park on 29 June 2022. The purpose of the search was in fact to arrest a person by the name of LS, who was suspected of committing child exploitation offences. As police prepared to conduct the search of the property, the applicant was seen leaving the house. Pursuant to s 68 of the Summary Offences Act 1953 (SA), the applicant was intercepted by police who initially thought he was LS and asked to produce his identification and his phone, which he did. Upon reviewing the applicant’s identification, police realised he was not LS. The applicant was asked further questions, without caution, about his connection to the property. He told police he had been living at the property for a few weeks and was in a relationship with the mother of the child of interest. The applicant had no apparent connection to LS apart from the fact he had been living at the property. Police decided to retain the applicant’s phone, purportedly pursuant to s 68, on the basis that he was either a suspect in the LS offending, or because of a general practice to seize electronic devices at or having been at a crime scene of the kind under investigation. The applicant returned to the property with police. During subsequent interactions with a detective at the property, the applicant was told of the investigation into LS and treated in a manner that would have conveyed that he was in fact not suspected of any involvement in the LS offending. In that context, the applicant was asked if police could look through his phone. He agreed. Thereafter, during the ongoing search of the property, police located a quantity of suspected controlled drugs. The detective who had been speaking with the applicant asked another detective (Detective Dunworth) to obtain the PIN for the applicant’s phone. Detective Dunworth, who was aware the controlled drugs had been found, approached the applicant and asked ‘what’s the PIN to your phone…’ The applicant provided the PIN. He was not cautioned before being asked for his PIN or told about the discovery of the drugs. The PIN was used to access the applicant’s phone and messages consistent with drug dealing were located. The applicant sought the exclusion of evidence of the contents of the phone on the basis of the failure to caution and what was said to be the unlawful retention of the phone.
Held: the application is upheld. The circumstances were such as to require the applicant to be cautioned or warned in some way before being asked to provide his PIN. The applicant was in a position of considerable disadvantage by virtue of the previous representations made about the purpose of looking through his phone. The applicant must have provided his PIN on assumptions consistent with those representations and without having been put on notice of the discovery of the controlled drugs. It would be unfair to the applicant to allow his provision of the PIN in those circumstances to be used against him and to permit the presentation of evidence of the content of the phone, obtained as a direct result of the failure to caution. Alternatively, the failure to caution enlivened the Bunning v Cross (1978) 141 CLR 54 discretion which should be exercised to exclude the evidence. Further, the retention of the phone after the initial interception of the applicant was unlawful. The suspicion that the applicant’s phone might afford evidence of the commission of an offence by LS was, in the absence of further information, speculative and redolent of mere idle wondering.
Controlled Substances Act 1984 (SA) s 32(2); Summary Offences Act 1953 (SA) ss 67, 68, 74A, 74D, 75, 79A, 81; Joint Criminal Rules 2022 R39.1(d), referred to.
R v Nguyen (2013) 117 SASR 432; Bunning v Cross [1978] HCA 22; (1978) 141 CLR 54; Middlin-Hannah v The Queen [2020] SASCFC 112; Ghani v Jones [1970] 1 QB 693; R v Lushington, ex parte Otto [1894] 1 QB 420; McQueen v Hawi [2008] NSWSC 136; Cramp v Commissioner of Police (NSW) (No 2) [2021] NSWDC 79; Queensland Bacon Pty Ltd v Rees (1966) 115 CLR 266; Bae v The Queen; Koo v The Queen [2020] SASCFC 7; George v Rockett (1990) 170 CLR 104; Prior v Mole (2017) 91 ALJR 441; McHugh v The Queen [2022] SASCA 5; R v Conley (1982) 30 SASR 226; Police v Hunt [2024] SASC 107; R v Dolan (1992) 58 SASR 501; R v Lobban [2000] SASC 48; (2000) 77 SASR 24, considered.

R v MATTHEWS-BOYSEN
[2025] SADC 30
Criminal Jurisdiction
Application for exclusion

The applicant is charged on Information dated 26 April 2023 with one count of trafficking in a commercial quantity of a controlled drug, namely 1,4-Butanediol (otherwise known as fantasy) contrary to s 32(2) of the Controlled Substances Act 1984 (SA). He brings an application pursuant to Rule 39(1)(d) of the Joint Criminal Rules 2022 seeking the exclusion of evidence obtained as a result of interrogation of his mobile phone, which was found to contain messages consistent with his involvement in drug trafficking, on the basis that the phone was unlawfully seized or retained by police.
The applicant argues further that the PIN for the phone was unlawfully or unfairly obtained as he was not provided with a caution, or some form of warning, before being asked to provide his PIN. The PIN was used by police to access the phone and it cannot now be known whether they would have been able to do so without the PIN. The applicant contends that both the ‘admission’ – here taking the form of the provision of the PIN – and the evidence derived from it, namely, the data extracted from the phone, ought to be excluded.
For the reasons that follow, I would uphold the application seeking the exclusion of evidence of the applicant’s provision of the PIN and the content of the phone. In the somewhat unique circumstances that arose after the applicant was first engaged by police, it was essential that a caution or warning be provided to ensure that he understood he was not obliged to provide his PIN. The need for a caution or warning was amplified in this case because the applicant had been told by police that they only wanted to review his phone to check for evidence of child exploitation offending which they were then investigating and which offences were said to have been committed by another. Although this was the premise upon which the applicant was asked, and apparently consented to police reviewing his phone, the situation at the time the applicant’s PIN was sought had changed as a quantity of suspected controlled drugs had been located in the house the applicant was connected with.
Even if the applicant was not then considered to be a suspect in relation to the drug offending or the child exploitation offending, the representations that had been made to him about the purpose for reviewing his phone were no longer accurate or complete. An inspection of the applicant’s phone carried the prospect of uncovering evidence of his responsibility for the drugs and some caution or warning was therefore required to allow the applicant to make an informed choice about whether he would provide his PIN, given that any messages or communications on his phone might tend to incriminate him in the commission of a drug offence.
The consent provided by the applicant to the police reviewing his phone on the basis of the representations earlier made to him was vitiated by the change in circumstances.
It would be unfair to allow the prosecution to deploy the contents of the phone – accessed as a result of the provision of the PIN – on the applicant’s trial for drug trafficking.
I would uphold the application on the further basis that the retention of the applicant’s phone was unlawful. As will be seen, when police first engaged with the applicant on 29 June 2022, they were operating on the assumption that he was in fact the person who was suspected of committing child exploitation offences then under investigation. On this premise, the applicant was asked to handover his phone. This constituted a search of the applicant pursuant to s 68 of the Summary Offences Act 1953 (SA) (SOA). Shortly after the applicant handed over his phone, police ascertained that the applicant was not who they thought he was. In an attempt to ‘place’ the applicant in the context of the investigation, he was asked some questions and disclosed that he had been living at the house where the offences under investigation were suspected of having been committed and was in a relationship with the mother of the child of interest.
The applicant had no other connection to the actual person of interest and police had no information to suggest that the applicant was involved in the offending being investigated, nor that his phone had been used by the alleged offender.
Despite this, police determined to retain the applicant’s phone – either because he was considered a suspect or because of a general practice of seizing and reviewing any electronic devices found, or having been, at a crime scene of this kind.
Although the evidence of the police was that the phone was retained pursuant to s 68 of the SOA, the precise source of the power to seize or retain the phone is a matter of legal controversy. Be that as it may, I consider that none of the possible sources of power to retain the phone in fact authorised its retention in the circumstances. There was no reasonable basis for the police to suspect that the phone might afford evidence of the commission of an offence; nor was it reasonably necessary for them to keep the phone for the purposes of their investigation into the alleged offender. The retention of the phone was unlawful or improper and directly facilitated the obtaining of the applicant’s PIN and hence the evidence the subject of this application.
Accordingly, I would have excluded the evidence in the exercise of the public policy discretion on this additional basis.
Background to the application
The charge arises from a search of a house on Marion Road, Mitchell Park (the house) on 29 June 2022 conducted by the Joint Anti Child Exploitation Team (JACET). JACET officers attended the property in furtherance of an investigation into another man who I will refer to as LS. LS was suspected of being involved in the production and dissemination of child exploitation material involving a young child thought to be living with her mother at the house, which was also occupied by LS. In the days leading up to 29 June, LS had sent a number of images to a covert police operative that appeared to have been taken in a communal area of the house.
On the afternoon of 29 June, police conducted a briefing in relation to the planned search of the house and arrest of LS. At that briefing, a picture of LS was disseminated. He was identified as the sole target of the search. The applicant had no connection to the LS investigation whatsoever.
Following the briefing, police took up staging positions on Marion Road. The covert operative who had been engaging with LS online maintained observations on the house.
At around 3:30pm, the covert operative reported to other police that a male had been seen leaving the property with a dog and was walking towards Marion Road. There is some divergence in the evidence about whether the covert operative informed other police that the male was thought to be LS.
In any event, the male who had been seen leaving the property was approached and intercepted on Marion Road by four or five police officers, at least two or three of whom initially thought he was LS.
The male was asked to produce his identification and his mobile phone. He produced his licence, which was quickly reviewed by the officer who appeared to have responsibility for the interception, a Detective Chadbourne. The evidence before me gives the impression that the male produced his phone almost simultaneously with his driver’s licence. Upon reviewing the driver’s licence, it became apparent to police that the male was not in fact LS. The male’s identity was confirmed as the applicant. As I have said, the applicant’s name had not come up at all in the investigation or briefing concerning LS and the applicant was at the time essentially unknown to police. Nor had it been suggested as part of the investigation into LS or during the briefing that LS was disseminating child exploitation material more broadly than to the covert operative, although that was obviously a possibility.
Having ascertained the applicant’s identity, police engaged him in conversation. He was asked where he lived. Again, the evidence as to what the applicant said in response diverged as between some of the witnesses. A number of officers gave evidence that the applicant said he had been staying at the house for a short period of time and was in a relationship with a woman living there, who I will refer to as NB, and who was thought to be the mother of the child the subject of the images.
As a result of this information and because the applicant had been seen leaving the property, but notwithstanding he had no discernible connection to the suspected offending by LS, Detective Chadbourne determined to retain the applicant’s phone for interrogation. She did so in purported reliance on s 68 of the SOA.
The applicant then accompanied a number of police officers back to the house where he waited out the front, having been told he could not enter the house as it was a crime scene. The applicant remained in the company of a Detective Patterson, during which time Detective Patterson informed him generally about the investigation into LS and conveyed by his manner of dealings with the applicant that he was not a suspect in that offending. Detective Patterson also asked the applicant if he minded if the police looked at his phone to check whether there was any child exploitation material on it. The applicant apparently consented to this course, remarking on his dislike for ‘paedophiles’. The applicant was otherwise allowed to move around freely as he was not under arrest.
Whilst this interaction was taking place, the house was being searched. During the search, police located what was suspected to be a quantity of controlled drugs. After the discovery of the suspected drugs, Detective Patterson asked another police officer – Detective Dunworth – to obtain the applicant’s mobile phone PIN. Detective Dunworth approached the applicant and asked him ‘what’s the PIN for your phone’. The applicant was not cautioned or provided any form of warning or information suggesting that he did not need to provide the PIN. The applicant told Detective Dunworth his PIN.
The PIN was subsequently used by the Digital Evidence Section of SA Police to extract data from the phone. It cannot now be known whether the extraction could have been performed without using the PIN.[1]
[1] VDP1, agreed facts [5], [7].
The evidence
The prosecution called Detectives Chadbourne (who is no longer a member of SA Police but who I will refer to for convenience as ‘Detective’), Patterson, Dalton, Dunworth and Federal Agent (FA) Martinovic. A bundle of affidavits and agreed facts were also tendered (VDP1). The evidence in chief of the relevant officers proceeded substantially by way of affirmation of the correctness of affidavits previously sworn by them and which formed part of VDP1 and in some cases some brief supplementary examination in chief.
I turn now to a summary of the evidence.
Detective Chadbourne
In June 2022, Detective Chadbourne held the rank of Detective Brevet Sergeant.
Together with other officers, Detective Chadbourne attended Marion Road, Mitchell Park on 29 June 2022 in preparation for conducting a search of the house and to arrest LS for suspected online child exploitation offending.[2] A briefing was conducted beforehand. Detective Chadbourne understood from the briefing that LS had sent child exploitation material to an online covert police operative posing as an adult female on 19, 20 and 21 June 2022.[3] As part of those communications, LS sent a ‘selfie’ to the covert operative,[4] such that police were aware of his appearance. The selfie was made available to police at the briefing[5] and Detective Chadbourne also accessed an image of LS on police databases.[6]
[2]     VDP1, Tab 5, [3].
[3]     T36-37.
[4]     T38.
[5]     T51.
[6]     T60; VDP4.
After taking up position on Marion Road, Detective Chadbourne was advised that an adult male with a dog had been seen leaving the house and was walking along Marion Road.[7] She approached the male in company with Detectives Dalton, Dunworth, Sutherland and Federal Agent Martinovic.
[7] VDP1, Tab 5, [4].
In an affidavit sworn on 24 January 2023, Detective Chadbourne described her subsequent interaction with the male in the following terms:
5.I approached this male who I now know to be Jack MATTHEWS-BOYSEN in company with Police DALTON, DUNWORTH, SUTHERLAND and MARTINOVIC and identified ourselves as Police then asked for proof of his identification [sic]. I asked MATTHEWS-BOYSEN to hand me his mobile phone which he did. My authority to seize the mobile phone was Section 68 Summary Offences Act (reasonable cause to suspect evidence in [sic] the commission of an indictable offence). I immediately handed the mobile phone to DUNWORTH.
6.After a brief conversation to confirm identification with MATTHEWS-BOYSEN, it was established he was not the male under suspicion of the online child exploitation offences. I then left MATTHEWS-BOYSEN with other Police and walked north along the footpath to [1/…] Marion Road, MITCHELL PARK where we identified [LS] standing on the front porch and I placed him under arrest for online child exploitation offences.
Detective Chadbourne confirmed in her oral evidence that the suspicion to which she was referring in [5] of her affidavit was a suspicion that the phone contained child exploitation material because the applicant had been seen leaving the property and was suspected at the time to be LS.
Although the above passage gives the impression that the applicant produced his identification before he was asked to hand over his mobile phone – which Detective Chadbourne confirmed in her evidence in chief[8] - Detective Chadbourne said that at the time the phone was seized, she thought the applicant was LS.[9] When asked to explain how it was that she thought the applicant was LS given she had seen an image of LS at the briefing, Detective Chadbourne continued:[10]
[8] T39.
[9] T36, 38.
[10] T51-52.
AI guess it was both a very general medium build, medium height. Nothing physically outstanding initially that would confirm identification. Mr Martinovic did obviously see a photograph, or some formal identification of Mr Matthews-Boysen to negate that.
QI take it that you can't now tell me whether you took with you to Marion Road any images that had been presented to you in the course of the briefing in relation to [LS].
AI can't recall.
QBut you would have been concerned to have a clear picture in your mind about what [LS] looked like, when you arrived on Marion Road.
AYes, yes.
QBecause this was a targeted investigation in that sense, wasn't it.
AThat's correct.
QYou were there looking to deal with [LS].
AThat's correct.
QBecause that's the person to whom the information from the covert operative related.
AYes, your Honour.

An image of LS and video footage depicting the applicant was tendered on the hearing of the application. The appearance of LS and the applicant are not such that it can be said that Detective Chadbourne’s misapprehension as to the applicant’s identity was unreasonable, particularly in circumstances where at least some of the evidence suggests that the covert operative provided information that the male was LS.
Having thereafter confirmed the applicant’s true identity, Detective Chadbourne said that a decision was made to nonetheless retain his phone because:[11]
AWe still couldn't negate that there - any of his potential involvement in the child exploitation material offending due to the conversation that we had at the time he stated he'd been living at the address, he was the current partner of the child's mother and the images, the child exploitation images that were taken were in a public area of the house where they weren't sort of secluded away in a bedroom, they were in an open lounge room area which anyone has access to.
QYou mentioned a conversation there. Can you best as you can, in terms of exactly what was said, advise the court who said what in that conversation.
AI approached Mr Matthews-Boysen and asked, identified ourselves as police and asked for some identification, which he produced. Then I asked for his mobile phone, which he again produced. Detective Dalton and Detective Dunworth were in close proximity to me. At some stage during the conversation I handed the phone to Detective Dunworth as I was speaking with Mr Matthews Boysen and Detective Dalton was making notes at the time.
QBut in terms of what was said, are you able to elaborate anymore than what you have.
AMr Matthew-Boysen said he had been residing at the address for a short period of time, it may have been a few weeks. He obviously said, stated his name and where he was residing. Apart from that I can't recall much more of that conversation apart from trying to establish his identity.
[11] T39-40.
Again, although this passage of the evidence suggests that the applicant produced his identification before his phone was seized, Detective Chadbourne disputed that she knew of the applicant’s identity before asking for his phone.[12] However, she accepted that the applicant having produced his identification, she ‘viewed it quickly’ before handing it to Detective Dalton:[13]
QWhen you viewed the identification quickly, did it become apparent to you that the name on the identification was not [LS].
AThat's correct, your Honour.
QSo did you know that the identification [sic] was not [LS] before you asked for the phone.
AIt was quite a fluid conversation, your Honour. So we approached Mr Matthews-Boysen, asked for his identification, asked for his phone. They both came out, I gave the phone to Detective Dunworth and the identification to Detective Dalton.
[12] T41.
[13] T41.
Detective Chadbourne was asked whether she ought to have administered a caution to the applicant before asking for his mobile phone given that, on her evidence, she then suspected him to be LS:[14]
QBefore you asked for his mobile phone, do you agree you should have given him a caution at that point.
AYes.
HIS HONOUR
QWhy do you think you should have given him a caution before you asked for his mobile phone.
AI guess thinking about it further now, I wasn't interviewing him at that point in time. I'd advised him that we needed to identify who he was. It's a, I guess confirm or negate what potentially was going to happen. So I think - I don't think, no, I wasn't required to give him a caution at that point time, I was trying to establish the identity first.
[14] T42.
Detective Chadbourne said further that, even if she was aware of the applicant’s identity prior to obtaining his phone, she would have nonetheless seized his phone for the following reasons:[15]
[15] T43-45.
QSo if you knew he was Jack Matthews-Boysen, would you still have obtained, or seized his mobile telephone.
AYes, that's correct, because any person who is residing in the house, we still need to, I guess negate their involvement in any potential offending. For example, we cleared [NB’s] phone as well. We seized that, it was triaged, to negate any potential co-offending in the matter, because the evidence can be destroyed so easily and so quickly, potentially with the push of a couple of buttons, we need to obviously preserve evidence, is of the utmost priority. To take, I guess, a holistic approach going into the investigation, where it was the residence where Mr Matthews-Boysen advised us he had been staying within the last few weeks. That was the time of the offending of [LS]. So we still needed to unequivocally negate any sort of potential co-offending.
QIf I can just break that down. At the time that you asked Mr Matthews-Boysen - sorry, do you say you asked Mr Matthews-Boysen where he was living, or what his relationship to the house was. How did that conversation come out.
AI guess it was just fluid, as part of trying to identify, confirm his identification. 'Can I please have your driver's licence. Thank you'. Detective Dalton took details of that, so the conversation naturally progresses to 'Okay, so we saw you come from that address, is that where you're living?'. 'Yes, I've been living there for the last', I can't recall the amount of period of time, but it wasn't - it may have been a few weeks, I don't recall it being an extended period of time. Mr Matthews-Boysen wasn't recorded on police systems at that address, so that was another, I guess something we needed to explore with him. He let us know he was the current partner of [NB] as well, who was living there with her two children. So we needed to, I guess, explore all avenues of potential.
QBut you didn't give him a caution before having that conversation with him, in relation to how long he had been living at the address, who he was in a relationship with, etc., etc.
ANo.
QDo you agree that you should have given him a caution when you were asking him questions in relation to how long he had lived at the address, what his relation to the address was.
ANo.
QWhy is that.
ABecause that was all in the process of trying to confirm the identification and where he fits, from coming from the house.
QSo to confirm the identification would be 'What's your address?' Obviously he's required to give his name, address. You might have asked for his phone number, but to ask additional questions, such as 'How long have you been living at that address?'. 'What is your relationship to that address?'. 'Who is your partner?'. Do you know - I don't know if you asked this, 'Do you know this child?', 'Do you know [LS]?'. Do you say that's all part of confirming his identification.
AThat's right.
QSo you don't think that there needed to be a caution given prior to asking all of those additional questions.
ANo.
Later in her evidence, Detective Chadbourne said that it was a general practice amongst JACET officers that if a device had been found inside a house at which it was alleged that child exploitation offences had been committed, that device would be ‘triaged’, even if it was a device belonging to a person who was ‘just visiting’ the house. Her evidence continued:[16]
[16] T53-54.
QIs that, just to be clear about that, simply because you took the view that if a device has been inside a house at which it is alleged that child exploitation offences have been committed, it's reasonable to suspect that device might afford evidence of the commission of an offence.
AAbsolutely, your Honour.
QIrrespective of the identity of the person who owns or is in possession of that device.
AThat's correct.
QAnd irrespective of whether there is or is not any information that suggests they might be complicit in any offending suspected to take place or had taken place at the relevant premises.
AThat's right, your Honour. There's, I think - electronic storage devices, they can hold anything. It doesn't matter whose you know, technical possession they are in, the offender could access, for instance, any device in the household and potentially look up child exploitation material, or save child exploitation material to multiple devices within that household. That's, I guess, the fluid nature of that electronic evidence. That's literally why each item is triaged, or negated, or we try and do that as reasonably as I guess we can within the household to negate any - to negate having to seize things that we don't need to for further analysis, but each and every electronic device that is located during a search, or that's in someone's possession is looked at.
QBut in this case, the phone that you located was not located in the house, was it.
ANo.
QThe phone that was seized, I should have said, was not located in the house. It was, in fact, located on who we now know as Mr Matthews-Boysen.
AThat's right.
QWho wasn't the person who was the target of your investigation.
AThat's right.
QI think I might have asked you this earlier, so forgive me if I did, but at the time that you seized and retained Mr Matthews-Boysen's phone, you didn't know how long he had been inside the house for on 29 June.
AThat's correct.
QBut you had some information from him to the effect that he had been staying at the property for a few weeks.
AThat's correct.
QAnd that few weeks period, did he define that as being the period leading up to 29 June, or did he speak more generally to 'I've been staying there for a few weeks'.
AI honestly can't recall, your Honour.
MS ARMSTRONG
QDo I take it from that then that it wouldn't have mattered how long he had been at the address for, but because you saw him leaving the address, you would always have searched or seized his phone.
AThat's correct. We, I guess from that conversation that established that he had been frequenting there, I guess that does - I guess it elevates that level of risk in my mind about the potential that evidence may be on his phone. That's it.
Detective Chadbourne said that having established the applicant’s identity, she had power to retain the phone pursuant to s 68 of the SOA. She did so for the following reasons:[17]
[17] T46-47.
AI guess my suspicion is still there, because from the conversation, Mr Matthews-Boysen said he had been residing there recently. He's had contact with the children, people in the household are - we can't negate their involvement unless we can negate it using obviously the digital evidence that we find or we don't find.
QI don't want to put words in your mouth, but are you saying essentially that once you learned of his association with the house in a bit more detail, you took the view that there was still a potential that he was involved in the CEM offending you were investigating.
AThat's correct. Obviously his association with [LS], his association with [NB]. We need to, I guess, investigate all avenues of any potential offending within that household, for the safety of the children, the child protection.
QYes; and even before you learnt of his identity, as Mr Matthews-Boysen, you had seen him, or had information that he had emerged from the house that was the subject of your inquiry.
AThat's correct.
QAnd where, on the information that you had been provided with, a person who was disseminating child exploitation material was residing.
AThat's correct.
QSuch material can be disseminated online, using mediums such as mobile phones.
AYes, your Honour.
QAnd you saw the person that was intercepted to have a mobile phone.
AYes, your Honour.
To the extent that in the above answer it was suggested that the applicant had an association with LS, that could only have meant an association arising from the fact the applicant said he had been living at the house for a period of weeks. There was no evidence of other information available to police that suggested any association between the applicant and LS.
Detective Chadbourne accepted further that the applicant’s name had not come up in the investigation relating to LS; nor did she have any information to suggest that anyone other than LS was involved in the suspected offending[18] or that the images had been disseminated to anyone other than the covert operative.[19]
[18] T47.
[19] T55.
Nonetheless, she considered the applicant to be a ‘suspect’ after he disclosed his association with the property and relationship with the child’s mother.[20] She said however that had he asked to leave, he would not have been prevented from doing so albeit his phone would have been retained.[21]
[20] T47-48.
[21] T50.
Detective Chadbourne said further that she in fact would have seized the applicant’s phone irrespective of whether she obtained the additional information from him concerning his connection to the house because of the general practice to which I have earlier referred.[22]
[22] T56-57.
After her conversation with the applicant, Detective Chadbourne left him in the company of other police and attended upon the property where she understood LS had been located.[23]
[23] T49.
Detective Dalton
Detective Dalton attended the pre-search briefing conducted by the covert police operative on 29 June 2022. Thereafter, she made her way with other police to a nominated rendezvous point in the vicinity of the house.[24]
[24] VDP1, Tab 10, [4].
The covert police operative involved in the alleged offending was maintaining observations on the property and advised police that a male with a dog was seen to leave the residence.[25] Detective Dalton, together with at least four other police,[26] intercepted the male. It was put to Detective Dalton in cross examination that one of the police officers put a hand on the applicant as part of their interception of him, to which she answered that she ‘couldn’t say’ but that ‘might have’ happened.[27]
[25] VDP1, Tab 10, [5]; T64.
[26] T62-63.
[27] T67.
Detective Dalton’s evidence was that at the time she and other police observed the applicant on Marion Road, she did not know his identity. She did not know whether the male was LS and did not think that the covert operative had provided information to that effect.[28] Detective Dalton agreed that apart from having information that the male had left the residence of interest, she had no other information about his connection with the property when police approached him.
[28] T66.
Detective Dalton said that after intercepting the male, she obtained his personal details by reference to a driver’s licence in the applicant’s name.[29] Having ascertained the man’s identity, Detective Dalton realised that he was not the person of interest.[30]
[29] VDP1, Tab 10, [5].
[30] T63.
Detective Dalton said that the applicant’s phone was obtained ‘around the same time’ as she was taking down his personal details but her recollection was concededly poor.[31] She said however that he provided information that he was in a relationship with NB and that ‘generally we examine electronic exhibits from a premises where there has been a dissemination of child exploitation material or digital evidence’.[32]
[31] T66-67.
[32] T67.
Detective Dalton recorded the information received from the applicant in her notebook.[33] No caution was provided to the applicant before he was asked the questions that led to the disclosure of his relationship with the mother of the child because ‘he wasn’t a suspect at that point’.[34]
[33] T67-68.
[34] T68.
I set out an exchange occurring later in Detective Dalton’s cross examination:[35]
QSo at the time his phone was seized, there was nothing to suggest that that phone might contain evidence.
ANo, but you never really know who is going to be at a premises when you attend a premises. So although we had initial information that [LS] was a suspect, you have to investigate everybody at the premises.
QEven if they've just been there two minutes, three minutes.
AWell that's part of your investigation.
[35] T71.
After the interaction with police on Marion Road, the applicant walked back to the house with Detective Dalton and at least one other police officer. Detective Dalton did not think the applicant was directed to return to the property as ‘he would have been free to leave if he wanted to, on the proviso that we could examine his mobile phone and ensure that he wasn’t implicated in the sexual abuse of the children that was occurring at that address’.[36]
[36] T69.
The applicant was left near the front fence to the property in company with Detective Dunworth.[37]
[37] T70.
Detective Dalton was unsure what would have happened if the applicant had asked to have his phone back.[38]
[38] T69.
Detective Dunworth
Detective Dunworth was in company with Detectives Chadbourne and Dalton on the afternoon of 29 June 2022. In her affidavit dated 5 August 2022, relied upon as her evidence in chief, Detective Dunworth said that at around 3:30pm, she and other police were advised that a male had been seen leaving the house walking a dog. The male was suspected to be LS.[39] Detective Dunworth subsequently confirmed during the course of her evidence that the information as to the suspected identity of the male was provided by the covert police operative.
[39] VDP1, Tab 6, [4].
As a result of this information, police moved to intercept the male on Marion Road.
As Detective Chadbourne was speaking with the male who, as we know, turned out to be the applicant and not LS, Detective Dunworth observed a sheath on his belt in which there was a knife which she subsequently seized. At this time, Detective Chadbourne had control of the male’s phone.
Detective Dunworth’s affidavit did not address the circumstances in which Detective Chadbourne came to have possession of the phone.
Following the discovery of the knife, the applicant was searched by Federal Agent Martinovic. Detectives Chadbourne and Dalton ‘walked with’ the applicant to the house.[40]
[40] VDP1, Tab 6, [6].
In cross examination, Detective Dunworth said that she ultimately came to have custody of the applicant’s phone, which she understood was retained pursuant to s 68 of the SOA.[41]
[41] T75.
Detective Dunworth agreed that her notes from the day record that the applicant provided a home address that was not the address of interest to police. She said however that if a person has been at an address considered to be a crime scene, ‘…that gives us reasonable grounds to suspect that he could have articles from that address which would be relevant to the offending…’[42]
[42] T76.
Detective Dunworth said that after the applicant and police returned to the house, a search of the house was conducted, during which a quantity of suspected controlled drugs was located. It was after that, according to Detective Dunworth, that Detective Patterson asked if she had the applicant’s mobile phone and if she could obtain the PIN from the applicant.[43] Detective Patterson was inside the house at the time he made this request of her. The applicant was outside. Detective Dunworth went outside and asked the applicant ‘What’s the PIN to your phone or something along those lines’. She did not tell the applicant that he did not have to provide the PIN and she did not tell him why she was asking for his PIN.[44] No caution was administered.[45]
[43] VDP1, Tab 6, [8].
[44] T84.
[45] T79.
Detective Dunworth was of the view that if the applicant did not provide the PIN, police would have considered whether recourse could have been had to s 74BR of the SOA, which confers power on a Magistrate to make an order that a person provide information or assistance to police that is necessary to facilitate access to or examination of data on an electronic device.[46]
[46] T80.

Detective Dunworth said that although the request from Detective Patterson came only after the drugs were located, the purpose of obtaining the PIN was to further the investigation into the child exploitation offences:[47]
QAs I understood your evidence a moment ago it was after the quantity of suspected drugs had been located that Detective Patterson asked you to get the PIN number.
AI believe it was, yes.
QAt that point in time, was it the case that really you understood Patterson to be asking you to get the PIN number for the purpose of furthering an investigation in relation to the suspected drugs.
ANo, because my understanding was that we would always have looked at the phone in regards to the child sex offences, that's absolutely normal process. So I don't think it even occurred to me - the drugs were quite separate, I had almost nothing to do with that, other than at some point being aware that something had been found they thought might be, but in regards to the phone my only understanding was that it could be relevant to the child sex investigation. So, no, that was my rationale, yes.
QBut Detective Patterson had not asked you to obtain the PIN number before the drugs, suspected drugs, were located.
ANo, but in some ways that's also not, that's not unusual, we are going through, you know, lots happening. We were searching for clothing, that was kind of the priority initially, and then I think the phone - I believe it was ‘Oh, and we need to check the phone’ amongst a lot of other things that were also happening within that time. So it didn't feel like there was delineation between: we're doing this investigation, stop, now we're doing something to do with the drugs. It was, you know, the investigation into the child sex offences that had happened at the house were ongoing throughout, so my rationale really didn't change as to why I asked for the PIN.
[47] T80-81.
Detective Dunworth agreed that at the time the applicant’s phone was reviewed, it was obviously known he was not LS and there was no information to hand implicating him in the child exploitation offending under investigation. Detective Dunworth understood that the only information connecting him to the house was that he had been seen emerging from the house and his partner lived at the address with her children.[48] Detective Dunworth said that this combination of circumstances ‘raised our suspicion…that that phone could have relevance to the investigation’.[49]
[48] T83.
[49] T83.
With respect to the general practice relating to the interrogation of electronic devices located during the course of an investigation into suspected child exploitation offending, Detective Dunworth said:[50]
AOkay. So we would look for all electronic devices at a premises initially and then depending on whether we would - depending on whether we have digital forensics with us, the kind of devices we would either leave it completely up to digital forensics to review devices, however, often with mobile phones we will also do a manual review. So we will actually physically look at them to see if there's obvious signs of offending on that phone and that could be looking at absolutely everything; so, photographs, videos, messaging, you know web addresses, anything that might suggest child exploitation material or similar offending.
[50] T82.
And later:[51]
[51] T85-86.
QWas there anything in the briefing that you attended that suggested that electronic devices belonging to people other than [LS] should be seized.
AIt wouldn't have been said outright but it absolutely would have been in all of our minds. Just because something isn't attributed to the person that we are interested in doesn't mean that it's not relevant to the offence or could be being used by the offender. So it would be normal for us all to know that any electronic devices from that house or in that house could be relevant to the investigation.
QEven electronic devices that are not in that house.
AIf they have come from that house in this scenario. So, shortly before we attended then yes, absolutely.
HIS HONOUR
QIs it the case even in relation to what is typically an individually possessed item like a mobile phone that you come across outside of the premises, albeit when the person whose phone it is has previously been inside at some point.
ASorry, your Honour.
QYes, that was a bit clumsy but I suppose what I'm getting at is that people normally retain control of their own mobile phones when they are outside of their residence, don't they.
AYes, correct.
QAnd so a fair assumption would have been that the phone that was found on Mr Matthews-Boysen was his phone.
AYes, yes.
QAnd you didn't have any information to suggest that Mr Matthews-Boysen was implicated in the CEM offending.
ANo.
QBut you say that because he had been seen coming from the premises, it was appropriate to retain custody of the phone even after his identity had been confirmed.
AYes and I think probably more specifically with this matter because we knew the offending had taken place at that house with a child that resided at that house. So knowing that he had a partner there, had just come from there raised that suspicion.
QI appreciate this is hypothetical but if another person had turned up to the property whilst the search was being conducted would you have seized their mobile phone.
AIt would depend on the circumstances. If they had strong connections to the premises, then yes, I think we would definitely be considering it.
QWell what was Mr Matthews-Boysen's strong connection, if any, to the premises.
AHis partnership with obviously [NB] and the fact that he had just come from there, would have been the two, yeah, the two factors.
QBut you didn't know if he resided at the premises.
ANo, no. He had given a home address but I also didn't know that he actually lived at that home address.
QBut his home address was not the Marion Road address.
ANo, it was a Mount Barker address.
QAnd it was [NB] that had the connection to the property, wasn't it.
AYes.
QMr Matthews-Boysen had a connection to [NB] on the information you received.
AYes, but that also would have meant that I then believed that he would have been spending a large amount of time with his partner. The Mount Barker address was his parents' address, which also made me think that he probably wasn't spending as much time there as he was with his partner at the Mitchell Park address.
Federal Agent Martinovic
Federal Agent (FA) Martinovic arrived at the applicant’s location on Marion Road shortly after other police. Detective Dunworth had already located a knife in the applicant’s possession and, for that reason, FA Martinovic conducted a frisk search of the applicant, during which he located a second knife.
Although not entirely confident, FA Martinovic thought there was conversation with the applicant about where he was living or had come from, as FA Martinovic had recorded in his notes ‘Boysen stated living at [the house]’.[52]
[52] T90.
FA Martinovic then walked back to the property with the applicant and Detective Dalton.[53] Other police were already in attendance and were speaking with LS outside the front door to the premises. FA Martinovic said police gained access to the house using a set of keys recovered from the applicant.[54]
[53] VDP1, Tab 8, [6]-[9].
[54] VDP1, Tab 8, [11]-[12].
In cross examination, FA Martinovic said that he ‘possibly’ kept a hand on the applicant after searching him and whilst walking back to the house, because of the discovery of knives in his possession. He said however that he did not think he would have told the applicant ‘you’re coming back to the house’ but may have said words to the effect of ‘we’re going back to the house’.[55] He did not think that another police officer directed the applicant to return to the house or to sit on the sofa at the front of the house thereafter. Whilst FA Martinovic did not himself tell the applicant he was free to leave, he considered that the applicant was in fact free to leave had he wished to.[56]
[55] T93-94.
[56] T96.
As to investigations of this kind more generally, FA Martinovic said that police would try to search all electronic devices found at a property where child exploitation offences were suspected of having been committed because of the prospect of an offender using different devices to secrete material.[57]
[57] T97.
On the assumptions that prior to seizing the applicant’s phone, police had information that the applicant had been seen leaving the address but were aware that he was not in fact the person of interest in the investigation, FA Martinovic said he would not have seized the applicant’s phone.[58]
[58] T97.
He said further that, on the assumption that the person with whom police were conversing on Marion Road was or was believed to be LS, a caution ought to have been given before questions were asked about where the suspect was residing because of the materiality of a connection between the suspect and the premises at which an offence was alleged to have been committed.[59]
[59] T99.
Detective Patterson
Detective Patterson fulfilled the role of an ‘overseeing supervisor’ on 29 June 2022.[60] He did not make any notes of his involvement in the events of that day. He first swore an affidavit based on his memory of events relating to the search on 10 July 2023.
[60] VDP1, Tab 4, para [3].
Detective Patterson attended a pre-search briefing that he recalled being conducted by Detective Chadbourne.[61] He understood from the briefing that the investigation concerned the dissemination of pictures of a child by LS to another person.[62] The applicant was not suspected of being a recipient of any such material.[63]
[61] VDP1, Tab 4, [3].
[62] T17.
[63] T23.
At around 3:30pm, Detective Patterson received information that the applicant had been intercepted by police having been seen leaving the property. Detective Patterson made his way to the property and engaged with the applicant who was ‘…out the front of the house with his dog.’[64]
[64] VDP1, Tab 4, [5]. See also T13.
In his affidavit, Detective Patterson said that he spoke with the applicant about the investigation into LS and inquired of the applicant’s association with LS. Detective Patterson said that the applicant ‘was not under arrest and was not at all suspected to be involved in the offences being investigated at that time’. He adhered to this position in his oral evidence,[65] remarking that he considered the applicant to be more of a ‘victim/witness in the matter’ and was trying to establish a rapport with him.[66]
[65] T8.
[66] T8, 11.
Despite this, Detective Patterson asked the applicant if he could search through his phone ‘as I wanted to check if it contained any child exploitation material or evidence relative to the [LS] investigation’.[67] He said that the purpose of searching the applicant’s phone was to ‘see if there’s any connection between that electronic device and the production of child exploitation material’[68] bearing in mind that ‘we knew that the [applicant] had been inside that address; we knew that that address was the crime scene, and the area where the child exploitation material had been produced’.[69] He added:
It's common practice for us to review any electronic devices that may have been in that house to review them to see if there’s any connection between that electronic device and the production of child exploitation material.[70]
[67] VDP1, Tab 4, [6].
[68] T8.
[69] T8.
[70] T8, 17.
At the time he made the request of the applicant, the phone was already in the custody of police.[71] Detective Patterson understood the phone had been seized when the applicant was intercepted on Marion Road,[72] placed into an evidence bag and secured inside the house.[73] Prior to asking the applicant if he could search the phone, Detective Patterson did not offer to return the phone to him.[74]
[71] T12.
[72] T12.
[73] T16.
[74] T16.
Detective Patterson took the view that police were empowered to retain the phone notwithstanding the applicant’s identity had been confirmed as someone other than LS and notwithstanding the applicant was not suspected of having committed any offence because ‘…we knew that the phone had been at the location of the offence at the house…’[75] and ‘…through my experience I know that the offender of the child abuse material may have used that phone to record anything, there may have been evidence on there…’[76]
[75] T16.
[76] T17.
According to Detective Patterson, the applicant ‘consented’ to him searching his phone, highlighting his ‘dislike of paedophiles’. As to the terms of the request made of the applicant, Detective Patterson said he asked the applicant if ‘he had any issues with me, or if he consented to me viewing his phone to see if there was any child exploitation material or any evidence of the offending that we were investigating’.[77] Detective Patterson said the applicant ‘consented to me looking at that phone and in fact he openly encouraged it…He said “yeah sure. No worries at all. I’ve got nothing to hide”’.[78]
[77] T8-9.
[78] T9.
When pressed to relay with precision the words he used when asking the applicant to search his phone, Detective Patterson said:[79]
[79] T11.
QDetective, a little while ago, you told me that you asked him if he had any issues with or consented to you reviewing the phone. Did you use that kind of composite phrase or was your inquiry of him more direct.
AIt was a composite phrase.
QAnd as best as you can tell me now, what were the precise words that you used when you made that inquiry of him.
AI asked him 'Do you mind if we search your phone in relation to child exploitation material?'
QDid he respond.
AHe said 'Yes, sure, I have no issues'.
MS ARMSTRONG
QAnd what did you say after that, or do.
AAfter that, I then obtained the phone. He didn't say anything else after that. I mean, we were involved in a general conversation and an open, relaxed conversation. He wasn't at all a suspect. If anything, I was trying to get a good rapport with him because he may have been a - or at least related to the victim of the offence, and I was talking to him as a normal member of the community.
Detective Patterson rejected the suggestion that he told the applicant that it was in his best interests to allow police to look through his phone.[80]
[80] T32.
At this point of their interaction, Detective Patterson was unsure of the applicant’s connection to the child the subject of the investigation, but the applicant subsequently told him that he was in a relationship with the child’s mother.[81] Later in his evidence, Detective Patterson said he learnt of the applicant’s relationship with the child’s mother before asking to search his phone.[82] The applicant’s connection to people inside the house made him a relevant person to the investigation.[83] He did not know if the applicant resided at the property[84] and had no information as to how long the phone had been inside the premises and whether it had been inside the premises on more than one occasion.[85]
[81] T9, 22.
[82] T22.
[83] T23-24.
[84] T18.
[85] T24.
Detective Patterson did not obtain the PIN for the phone from the applicant.[86]
[86] T11.
As the applicant was not a suspect, he did not consider it appropriate to provide a caution.[87]
[87]T11.
Detective Patterson said that he did not tell the applicant he had to remain at the house. In fact, he said that the applicant asked ‘reasonably early on’ in their interaction at the front of the house if he could leave and Detective Patterson told him ‘he could if he wanted to’:[88]
[88] T14.
QDid you have that conversation with him before or after you asked him if he minded the police searching through his phone.
ABefore.
QSo, you say you told him or he was otherwise aware before you made the request about the phone that he was free to leave.
AThat's correct.
Q. Had you yourself told him that he was not under arrest at that point.
AHe asked me if he could go, and I said yes. He wasn't suspected of anything at all.
QYes, but after asking you that question, he did not leave the area.
AHe did a little bit, and he walked his dog and he moved around freely, and then at some stage, he sat on a lounge out the front, like, there was a lounge there that he sat on. He was waiting, he was just waiting.
Detective Patterson agreed that after the applicant was intercepted by police, he walked back to the property in company of the police officers who had approached him.[89] He denied directing the applicant to sit on a couch at the front of the house.[90]
[89] T30.
[90] T30.
Detective Patterson did not tell the applicant he was not under arrest, but maintained that ‘[the applicant] was well aware that he could come or go if he pleased’ and did just that, walking to a neighbouring property.[91] It was suggested to Detective Patterson that the applicant did not in fact attend upon a neighbouring property. Detective Patterson disagreed.[92]
[91] T15.
[92] T29.
Detective Patterson said the applicant was not under the control of the police but was not permitted, and was told that he was not permitted,[93] to enter the property as it was a crime scene, albeit acknowledging that the child of interest and the child’s mother remained inside the house during the search.[94] He disagreed that the applicant had been told that he was not allowed to leave.[95]
[93] T30.
[94] T15-16.
[95] T30.
When Detective Patterson reviewed the applicant’s phone, he identified communications relating to drug dealing and drug use.[96] He subsequently handed the phone over to another police officer, Clare Lock.[97]
[96] VDP1, Tab 4, [7]; T20.
[97] T20.
Issues for determination
The occasionally conflicting evidence of the various police witnesses called by the prosecution raises the following issues for consideration:
Was the initial seizure of the applicant’s phone lawful and, if so, was the retention of the phone lawful once the applicant’s identity had been ascertained?
Was the applicant under de-facto arrest at any time following his interception by police on Marion Road?
Should the applicant have been cautioned before he was asked questions about his connection to the property and/or when Detective Dunworth asked him to provide his PIN?
The failure to Caution
It is convenient to first address whether the applicant ought to have been cautioned before he was asked to provide the passcode to his phone or at an earlier point. If a caution was required, but not given, it will be necessary to consider whether it would be unfair to the applicant to allow the prosecution to use content extracted from his phone against him or whether the evidence should be excluded in the exercise of the Bunning v Cross (1978) 141 CLR 54 discretion.
The framework within which this issue is to be resolved is that, even after ascertaining the applicant’s identity on Marion Road, Detective Chadbourne said she was unable to negate his potential involvement in or connection to the alleged offending of LS. It was for that reason that she decided to retain the applicant’s mobile phone. Indeed, she went so far as to say that the applicant was, in her mind, a suspect, as a result of his disclosures about his relationship with NB and that he had been living at the property for a short period.
Detective Dalton, who was present when the applicant’s phone was seized and who took down the applicant’s personal details and recorded information he provided concerning his relationship with the mother of the child, was of the view that whilst the applicant was not ‘a suspect at that point’ – and hence was not cautioned[98] - it was nonetheless appropriate that his device be seized because ‘you have to investigate everybody at the premises’.
[98] T68.

It will be recalled that Detective Dunworth came to take possession of the applicant’s phone, which she understood had been retained pursuant to s 68 of the SOA. Although Detective Dunworth’s notes record that the applicant had provided a residential address that was not the address of interest, her view was that if a person has been at an address considered to be a crime scene, police have reasonable grounds to suspect that person could have items from that address which would be relevant to the offending. She said further that after the applicant disclosed his connection to NB and having emerged from the house, that ‘raised our suspicion in regards to the fact that that phone could have relevance to the investigation’.[99]
[99] T83, 86.
The consensus appears to be that, even before the discovery of the suspected controlled drugs, it was contemplated by the officers involved in intercepting the applicant that his phone might afford evidence of the commission of the child exploitation offences. This was the basis upon which police considered they were empowered to retain the applicant’s phone. Plainly enough, had any such evidence been detected on his phone, difficult questions would have arisen for the applicant.
Whether that suspicion was reasonable is a matter that will require examination in a different context, however, for present purposes, I consider that, objectively, the applicant was within a class of people of considerable interest to the police investigation and police subjectively thought his phone might well be a source of evidence.
Returning to the search of the property, Detective Dunworth said that it was only after the discovery of a quantity of suspected controlled drugs that Detective Patterson asked her to obtain the applicant’s PIN, which she did by asking him ‘what’s the PIN to your phone’ or words to that effect.[100]
[100] T80.
The evidence does not establish that Detective Dunworth knew anything more about the bag in which the drugs were located or whether it could be linked to the applicant.
According to Detective Patterson, the applicant was not a suspect and was considered to be more of a ‘victim/witness’. In his affidavit, Detective Patterson said that he had discussed with the applicant in general the investigation into LS; told him he was free to move around; and generally treated him in a manner consistent with his view that he was not suspected of being involved.[101] In this context, Detective Patterson asked the applicant if he could search his phone to check if it contained any child exploitation material relative to the LS investigation.[102] The applicant apparently gave his consent.
[101] VDP1, Tab 4, [6].
[102] T8, 18.
Detective Patterson’s evidence was that it was not necessary for a caution to be given to the applicant before his PIN was sought. He was of the view however that the applicant ‘obviously had a close connection to the house and a close relationship with the people inside’.[103] The house was considered to be a ‘crime scene’.[104]
[103] T18.
[104] T23.
Detective Patterson’s position was that he was not aware of the discovery of the suspected drugs at the time he asked to review the applicant’s phone.[105]
[105] VDP1, Tab 4, [6]; T20-21.
When is a caution or warning required
It is not possible to be categorical about the time at which a caution should be given and the consequences of a failure to do so. The circumstances of the case, and the fairness of using anything an accused says in the absence of a caution, call for a fact specific assessment.[106] It can be said that, at the very latest, a caution must be given when the police have moved into the accusatorial stage of an investigation,[107] have reasonable grounds to suspect a person has committed an offence or have decided to arrest a suspect.[108]
[106] R v To (2006) 96 SASR 1, [10]-[12] (Vanstone J); R v Dolan (1992) 58 SASR 501, 511-512 (Olsson J).
[107] R v Murphy (1996) 66 SASR 406, 412 (Doyle CJ).
[108] R v Dolan (1992) 58 SASR 501, 505 (King CJ); R v Tracey (No 5) (2005) 93 SASR 101, 111 (Nyland J).
However, fairness may dictate that a caution – or something approximating it - be provided notwithstanding police are still conducting inquiries or investigations and notwithstanding no decision has been made to arrest a person.[109] Clearly, however, once such a decision has been made, the need to give a caution is an indispensable requirement of fairness.
[109] Van der Meer v The Queen (1988) 62 ALJR 656, 661 (Mason CJ); R v Dolan (1992) 58 SASR 501, 505 (King CJ), 511 (Olsson J).
In considering whether a caution ought to have been given outside of the ‘accusatorial’ stage of a criminal investigation having been reached, Olsson J remarked in R v Dolan (1992) 58 SASR 501 at 512:
At the end of the day what is essentially in issue is the ultimate test of fairness. The reports are littered with decisions of judges of this Court which indicate the adoption of a broad, case by case, consideration. It is, of course, well established that, once it be demonstrated that the relevant police officer entertained such a strong and well-founded suspicion of the person interviewed that it would have been wholly unreasonable not to have decided upon an arrest and a caution is not given, then the conversations in question will normally be excluded...However, it may well be that, in some instances, as a matter of common fairness, a caution should be administered well prior to that stage.
Doyle CJ confirmed in R v Murphy (1996) 66 SASR 406 at 414 that whilst a caution must be given at the commencement of the accusatorial stage of an investigation – a point marked by the existence of reasonable grounds to suspect a person has committed an offence – that does not exhaust the requirements of fairness. In some cases, it will be appropriate for police to inform a person that he or she is a possible suspect, notwithstanding the accusatorial stage has not been reached. The Chief Justice said:
In a particular case it might be necessary for a police officer who is questioning a person, not a suspect, to bring to that person’s attention the fact that his or her possible involvement is under consideration. That might be necessary if, for some reason, the person is at a disadvantage because his or her attention has been diverted from the significance of the matter under consideration…if the person is not aware of the significance of the occasion (for example, if the person though that the inquiries related to a minor matter only when in fact they related to a serious matter), or if the person is under the impression that the police are making casual inquiries only, or if the person thinks for some reason that there is no need to give careful consideration to his or her answers. In such a case fairness might well require the police, on one way or another, to alert the person to the fact that the questions being put relate to a serious matter and that they will include matters relevant to the possible involvement of the person questioned.
In R v Johnson (2004) 143 A Crim R 395 at [53], Sulan J expressed a similar view in a case of murder:
Whether a caution should be administered depends upon the circumstances of each case. If a person is under arrest, or if the police intend to arrest a suspect, it is clear that in most cases the failure to administer a caution will render those conversations as having been unfairly obtained. There may also be instances in which a police officer is undecided and does not suspect the person interviewed, but where fairness dictates that a caution be given.
Whether a caution or some form of warning[110] ought to have been given therefore calls for a more detailed analysis than simply asking whether the “accusatorial” stage of an investigation has been reached. It is too narrow a view of the law to suggest that is the only circumstance in which a caution may be called for.[111] Amongst other things, consideration must be given to the nature and extent of information in the possession of police and their intentions at or around the time of an impugned interaction.
[110] See, eg, Thomas v The King [2024] SASCA 51, [29].
[111] R v Trotter (1992) 58 SASR 223, 237-238 (Perry J).
In some cases, the failure to provide a caution to a person who is considered to merely be someone of interest to police, but not a suspect, will ground the exercise of a discretion to exclude evidence. Much will depend on the setting within which any relevant conversation occurs. In R v Bueti (1997) 70 SASR 370, Doyle CJ held that the accused should have been cautioned by police when they invited him to attend a police station for the purpose of providing a statement, notwithstanding they did not then suspect him to be involved in a conspiracy to commit armed robbery. Doyle CJ identified the relevant question as follows (at 377):
The question is whether, notwithstanding their belief that Mr Bueti did not intend to encourage the commission of the robbery, a caution should have been administered...
The importance of administering a caution before a suspect is questioned is well established. The administration of the caution tends to negative any suggestion of involuntariness or of unfairness...
It is the unfairness of the use at trial, of answers obtained without the administration of a caution, which gives rise to the judicial discretion to exclude answers obtained in this way, even though they are made voluntarily. The discretion does not arise only if and when the unfairness might make the admissions unreliable, but also because ‘no confession might have been made if the investigation had been properly conducted.’
...
The fact that an interrogation has reached the accusatory stage is an indicator that fairness will require a caution be given before further questions be asked, if the answers are to be used at trial. But there may be other circumstances that make it unfair to use answers obtained without the administration of a caution. As I said in R v Murphy (at 414), the requirements of fairness are not to be turned into fixed categories, and the decided cases should not be taken as stating exhaustively what may be required if fairness is to be observed. While it is possible unfairness in the use of the answers at trial that enlivens the discretion, the fairness of the manner in which the police dealt with the suspect becomes relevant.
Doyle CJ found that the police had sought to ‘explore a topic through which ran a rather fine line dividing innocence from guilt’ with the accused, such that fairness required a caution be given even though police did not consider him a suspect.
In R v Kamleh (2003) 226 LSJS 4 at 6, Gray J held that a caution may be required even when police conducting an interview do not believe the interviewee to have been involved in an offence. As Gray J said:
Whether or not a caution should be given will depend upon the weighing of the information possessed by the police and their belief about the status of the person being interviewed.
A caution may also be required where police are seeking information from a person of interest that might be used to obtain other, incriminatory evidence against the person. As Kourakis CJ observed in Middlin-Hannahv The Queen (2020) 137 SASR 366 at [86]:
The privilege against self-incrimination is not limited to the right to refuse to answer questions. The privilege extends to the handing over of documents which may incriminate. It may undermine that privilege if a police officer were to seek assistance from a suspect to access his or her documents, which the police officer believes may contain incriminatory evidence, without informing the suspect of his or her privilege not to facilitate the seizure of that documentary material if it may be incriminating. Of course, a failure to warn is only legally significant if the request is made at a time, and in circumstances, which would so compromise the privilege that it would cause forensic unfairness in a subsequent criminal trial.
Just as the need to give a caution is determined on a case by case basis, so too is the content required in a caution. In most cases, a general caution advising a person that they are going to be asked questions and that they do not have to answer those questions but that anything they do so may be used against them will suffice. However, the increasing use of electronic devices in the commission of criminal offences (or as sources of evidence of such offences) may require a more nuanced caution to be given so that a person asked, for example, to provide a password or PIN code to access an electronic device appreciates that the privilege against self‑incrimination extends to such requests or demands.
This situation was explored in Thomas v The King [2024] SASCA 51, where the Court of Appeal observed that, depending on the circumstances, before a request is made of a suspect to provide a PIN, it may be necessary to give a more ‘word-specific’ caution. In that case, police attended a fire that they suspected had been lit by the accused, who was a CFS volunteer. The accused was given a general caution prior to being interviewed by police at the scene. In the course of that interview, the accused asked whether he would be required to attend the police station the following day, to which police responded ‘we’re going to deal with this now’ and ‘I need you to hand me your phone over’. The accused was then asked ‘what’s the access code to get into the phone’. The accused offered to deactivate the phone, and was told ‘no, no, no, no’ and asked ‘just tell us the access code please’. It would seem the accused was unable to explain what the PIN was and endeavoured to do something on the phone, prompting police to tell him ‘What, what, just, just stop…Show me how you unlock it’. The accused then showed police how to unlock the phone. The PIN was noted and the phone was seized.
Whilst the arson charge against the accused was ultimately discontinued, the subsequent interrogation of the accused’s phone uncovered child exploitation material.
On the accused’s appeal against conviction, the Court of Appeal observed that whilst a word-specific caution regarding the privilege against self-incrimination would not always be required in the context of a request to disclose a PIN, the circumstances may give rise to a need to adjust the terms of a caution to ensure it is effective at communicating to a person their rights (at [32]-[33]):
We accept the force of the appellant’s submission that even where a person is cautioned about answering questions, an instruction to do an act may well, in the particular context, warrant a conclusion that the person was nevertheless given no real choice about doing that act.
Thus, to take a simplified example, a person might be cautioned in ordinary terms against answering questions, and then have their phone seized lawfully but with an accompanying peremptory demand to unlock the phone that could not be interpreted as anything other than giving the person no choice but to do so. In such a case, the circumstances might well dictate that the caution was insufficient as the demand for the PIN had become effectively associated with the exercise of the search power.
The Court referred to the coercive power to obtain a PIN pursuant to s 74BR of the SOA and the limited circumstances in which that power could be deployed as reinforcing the importance of couching any request for a PIN in terms that did not convey the absence of a choice to provide it (at [34]-[35]):
However, the existence of Part 16A highlights the importance of police not conveying a request for a PIN in terms that risk conflating that request with an exercise of the search power under, for example, s 68 of the Summary Offences Act.
Recognising this possibility does not, however, recommend a hard rule that a person must be cautioned specifically before being asked for a PIN. The circumstances of the caution and ensuing exchange might well warrant the conclusion that while the caution was in general terms, the person was given a genuine choice. We do not accept that it is always necessary to give a word‑specific caution regarding the privilege against self-incrimination when it comes to disclosing a PIN.
Although the appeal was upheld on alternative grounds, the Court concluded that the giving of the initial caution, combined with the terms and context in which the police spoke with the accused about his PIN, meant that it could not be said the PIN had been obtained in circumstances that would have rendered its use against the accused to access his phone unfair.
Where a conclusion is reached that a caution ought to have been given but was not or was not given in adequate terms, a number of consequences may follow. The failure to caution may render a statement made by an accused involuntary. It may enliven the residual discretion of the trial court to exclude evidence the admission of which would operate unfairly to the accused. It may also amount to conduct that enlivens the Bunning v Cross (1978) 141 CLR 54 discretion.
There are two recognised discretions that have as their focus preventing forensic unfairness to an accused. The first, known as the Lee discretion, is generally said to be applicable only to confessional evidence and was economically described by Gibbs CJ in Clelandv The Queen (1982) 151 CLR 1 at 5:
A confession will not be admitted unless it was made voluntarily, that is in the exercise of a free choice to speak or be silent. But even if the statement was voluntary, and therefore admissible, the trial judge has a discretion to reject it if he considers that it was obtained in circumstances that would render it unfair to use it against the accused.
In Duke v The Queen (1989) 180 CLR 508 at 513, Brennan J said of the Lee discretion:
...it is...too confined a view to regard the unfairness discretion as applicable only to those cases where unreliability in the confession might have been produced by impropriety or unlawfulness on the part of the investigating police...the unfairness against which an exercise of the discretion is intended to protect an accused may arise not only because the conduct of the preceding investigation has produced a confession which is unreliable but because no confession might have been made if the investigation had been properly conducted. If, by reason of the manner of the investigation, it is unfair to admit evidence of the confession, whether because the reliability of the confession has been made suspect or for any other reason, that evidence should be excluded.
Strictly speaking, what is in issue in the present case is not a confession or admission (save to the extent that the applicant disclosed the PIN to the phone which admits of a close connection with the phone) but evidence derived directly from a statement made by an accused in response to a question that he did not have to answer, but was not told as much. In such a case, it is sometimes said that the discretion that arises for exercise is a residual or ‘general unfairness’ discretion. The existence of such a discretion was recognised in Lobban v The Queen (2000) 77 SASR 24 and was expressed to be capable of application to evidence of any description where its admission would be unfair to the accused in the sense of being productive of an unfair trial.
In Police v Dunstall (2015) 256 CLR 403 at [26], five members of the High Court summarised the discretions available to a trial judge, adverting to the acknowledgment by intermediate appellate courts of a general unfairness discretion: [112]
The exclusion of evidence in a criminal proceeding in the exercise of a “fairness discretion” is generally understood to refer to the principles explained in R v Lee (the Lee discretion). The Lee discretion forms part of the special body of rules applying to the admission of confessional statements. In criminal proceedings, there are two settled bases for the discretionary exclusion of on-confessional evidence, including “real” and circumstantial evidence. The first is where the probative value of the evidence is outweighed by the risk of prejudice to the defendant (the Christie discretion). The second is where the evidence has been tainted by illegality or impropriety on the part of the law enforcement authority (the Bunning v Cross discretion). The rationale for the latter discretion is not so much a concern with fairness to the defendant as with the public policy of not giving the appearance of curial approval to wrongdoing on the part of those whose duty is to enforce the law. These three discretions correspond with the exclusionary discretions that apply in criminal proceedings under the Uniform Evidence Acts. In addition to these bases for discretionary exclusion of evidence in criminal proceedings, intermediate appellate courts in other Australian jurisdictions have also identified a residual common law discretion to exclude admissible evidence on the ground of unfairness.
[112] Having not overruled Lobban, it remains good law in this State and I am bound to follow it: see, eg, R v Crawford (2015) 123 SASR 353, [20], [85]; Mullen v DPP (SA) (2020) 136 SASR 274, [53].

As no such information was given to the applicant, it necessarily follows that in determining whether to provide his PIN, he must have been proceeding on the misapprehension that police were then only investigating the child exploitation offending for which LS was the prime suspect and in respect of which the applicant was plainly being treated by Detective Patterson as though he was not a suspect. The purpose for which Detective Patterson told the applicant that he wished to review his phone, together with the surrounding circumstances, must have created a false sense of security in the applicant’s mind about his status and, I infer, would have coloured his decision to provide his PIN.
I add that although Detective Patterson maintained that the applicant was not a ‘suspect’ in relation to the LS investigation – which is said to contraindicate the need for a caution or warning to be given - that is not determinative of whether a caution or some form of warning ought to have been administered particularly after the discovery of the suspected controlled drugs. Moreover, and as I have said, it cannot be overlooked that Detective Chadbourne was of the view the applicant was a suspect in the LS offending after he disclosed his connection to the property and NB and that all police considered there to be a sufficient basis on which to retain the applicant’s mobile phone, notwithstanding that they had no information tending to suggest that LS had disseminated the child exploitation material to anyone other than the covert operative and notwithstanding that the applicant’s name had not otherwise come up in the course of the LS investigation. Even absent the discovery of the drugs, there is a firm basis upon which it could be said that a caution of some description should have been given to the applicant before his PIN was sought.
The position is a fortiori after the discovery of the drugs because, as I have said, at the time the applicant was approached to provide his PIN, he must have been proceeding on the assumption that the reason behind the request was to assist police with the LS investigation. Had the applicant been told of the discovery of the drugs, it is not difficult to contemplate that his response to the question that Detective Dunworth posed may well have been different, subject to the matter I next address.
I also consider that the form of words used by Detective Dunworth was, unintentionally, apt in the circumstances to convey to the applicant that he really had no choice whether to provide his PIN. I accept that Detective Dunworth did not expressly use words of compulsion or obligation; but equally, the words she used did not carry the impression that the applicant was free to decline to provide it if he wished to, particularly in circumstances where his phone had already been coercively seized. That is to say, the words did not convey a choice.
Construed literally and in the context of (1) the applicant being intercepted by police on Marion Road and having had his phone seized; (2) accompanied back to the property in the presence of two police officers; (3) told he could remain out the front of the property during the search; (4) engaged in conversation by Detective Patterson as I have recounted, I am satisfied that the form of words used by Detective Dunworth did not convey that the applicant had a choice to decline.
Moreover, and irrespective of whether the request made by Detective Dunworth conveyed a choice to the applicant to decline to provide his PIN, an important piece of information – namely, a caution or warning - that could have assisted the applicant in making an informed choice, was not provided to him. As I have said, the circumstances known to police had changed quite significantly between Detective Patterson obtaining the applicant’s ‘consent’ to review his phone and Detective Dunworth approaching him for the PIN. There is no evidence that when asked for his PIN, the applicant was aware of the discovery of a quantity of suspected controlled drugs. I consider that the applicant’s consent was essentially overtaken by the change in circumstances.
I note Detective Dunworth’s evidence that the investigation into the drugs was essentially of no concern to police. I do not think that matters. Detective Dunworth was aware that suspected drugs had been found in the house. She was aware that the applicant was in a relationship with an occupant of the house. Other police had information that the applicant was living at the house. He was therefore one of three adults connected with the house who may have been the owner of the drugs. It is a notorious fact that mobile phones are a valuable source of evidence of drug trafficking activities. It may be that upon the mere discovery of the drugs (and noting that it is not entirely clear whether FA Martinovic had by this time reported to other police his discovery of correspondence in the applicant’s name in the bag in which the drugs were secreted), there was insufficient evidence to charge the applicant with an offence. However, ‘…if he were trafficking, the probability of finding text messages to that effect was high, and only the PIN stood in the way of that discovery’.[120]
[120] Middlin-Hannah v The Queen (2020) 137 SASR 366, [94] (Kourakis CJ).
It may be that Detective Dunworth was completely unaware of the conversations that Detective Patterson had earlier with the applicant which necessarily framed the circumstances in which Detective Dunworth sought the applicant’s PIN. Indeed, Detective Dunworth was placed in a difficult situation for this very reason: she had not been dealing with the applicant and had been asked by Detective Patterson to obtain the applicant’s PIN. Be that as it may, it does not, to my mind, change the position. The focus of the current inquiry is not the propriety of the conduct of police, but whether it would be unfair to the applicant to allow the prosecution to use evidence obtained from an examination of his phone in circumstances where no caution or warning was given to him before he was asked to provide his PIN.
Similarly, I do not think it matters that Detective Patterson was unaware of the discovery of the drugs and that Detective Dunworth was, on the prosecution argument, simply acting as his ‘agent’ such that, because Detective Patterson did not know of the discovery of the drugs, there was no reason for Detective Dunworth to provide a caution. It may be doubted that the need to give a caution or warning to a person in the applicant’s position could be avoided by enlisting the assistance of an alternative police officer to obtain certain information. More importantly in this case, Detective Dunworth knew of the critical information which had just been acquired and which added to the information she was already cognisant of about the applicant’s association with the property. Based solely on what Detective Dunworth knew, there was a need to provide a caution or warning of some description. Indeed, based on what was known from the outset, and the view that was being taken in relation to the applicant’s phone, it is more than arguable that a caution was required in any event.
At the very least though that need was amplified in this case because of the representations made by Detective Patterson. Again, it matters not whether Detective Dunworth knew what the applicant had been told: the question is whether a caution or warning was required as a matter of fairness.
To return to Murphy, the applicant was in a position of considerable disadvantage requiring the giving of a caution or some form of warning here because he had been assured by Detective Patterson that the police (1) only wanted to review his phone for the purpose of their investigation into LS and (2) the manner in which Detective Patterson dealt with the applicant would have conveyed that he was not a suspect in that investigation and hence had no reason to be cautious. However, by the time the PIN was in fact sought from the applicant, it was known to police that a further offence had potentially been committed at a property that the applicant was connected to. The failure to bring that discovery to the applicant’s attention or to provide him with a warning or caution of some description at the time his PIN was sought unfairly disadvantaged him in deciding whether to provide his PIN in the event that he did not consider the request to be obligatory.
Had the applicant been informed that drugs had been located during the search and had he been cautioned, he may well have declined to provide his PIN. That must follow as a matter of reasonable inference once it is accepted that the applicant provided his consent to his phone being reviewed in the context only of the LS investigation. I am satisfied therefore that the failure to provide some form of caution or warning to the applicant, or at the very least to put him on notice about the discovery of the suspected controlled drugs before asking him to provide his PIN, had a material effect on the applicant’s position. In particular, I am satisfied on balance that had such notice or a warning been provided to the applicant, it may well be that no ‘admission’ in the form of the provision of his PIN would have been made.
I reject the submission of the prosecution that, even if the circumstances in which the PIN was obtained give rise to unfairness, the content of the phone, as a form of derivative evidence, ought to nonetheless be admitted. That submission overlooks that, on the evidence before me, the police may not have been able to access the content of the phone but for the ‘admission’ – in this case, the PIN – having been extracted from him in unfair circumstances.
It would perpetuate the unfairness to the applicant to permit the prosecution to lead evidence obtained as a direct result of the provision of the PIN, without warning or caution, in circumstances where it may well be that, but for the PIN, the police would not have been able to interrogate the phone.
In many situations involving the making of an admission where no caution has been given, it may be that the only evidence liable to exclusion is evidence of the admission itself. That is because the purpose of the caution is to inform a suspect or person of interest to the police of their privilege against self-incrimination and their right to decline to answer questions. It is the infringement of that right, and the subsequent attempt to deploy it to further a criminal prosecution against an accused, that jeopardises the fairness of an accused’s trial. It may be that derivative evidence marshalled as a result of investigations based on information obtained from the admission will not always fall for exclusion.
However, that cannot always be the case. Indeed, it would render the privilege against self-incrimination and right to silence somewhat inutile if evidence obtained in consequence of an admission made in the context of a failure to caution, could nonetheless be deployed against an accused in all circumstances. It is not difficult to appreciate how a tactical failure to caution a suspect in the hope that an incriminating comment might be made thus facilitating other forms of investigation or inquiries may be exploited. The failure to caution would, in those circumstances, have no material consequence.[121]
[121] Cf Middlin-Hannah v The Queen (2020) 137 SASR 366, [153] (Livesey J).
In any event, if the data from the phone falls outside the scope of the Lee discretion, it would nonetheless fall for exclusion by reference to the ‘general unfairness’ discretion. In either case, where the evidence before me is that the police used the PIN to interrogate the applicant’s phone and that they may not have been able to do so without the PIN, I am unable to accept the argument of the prosecution that any unfairness could sound only in the exclusion of the passcode, and not the extraction of data from the phone obtained by the use of the PIN.
If I am wrong about that I would have otherwise determined to exclude the phone evidence in the exercise of the public policy discretion on the basis that the failure to caution or warn constituted a form of impropriety insofar as it had the effect of circumventing the applicant’s right to silence. Whilst I would not find that the failure to caution was deliberate and that the cogency of the evidence was not compromised, it came about in circumstances that, I consider, obviously indicated the need for a caution to be given and hence involves an element of recklessness. The fact that it was thought that no caution was required also indicates – at least on my findings – that perhaps too narrow a view has been taken of the circumstances that might give rise to a need for a caution.
Conduct by police officers that tends to undermine the integrity of the suite of common law protections that a person in the applicant’s position has available to them should not lightly be dismissed. The privilege against self-incrimination and the incidental right to remain silent must be jealously protected. That requires that the evidence – both of the ‘admission’ as to the PIN and the evidence obtained in direct consequence of it – be excluded in order to maintain the integrity of the rights that were available to the applicant and to avoid the appearance of judicial acquiescence in conduct which has the effect of undermining those rights.
For these reasons, I would exclude the evidence of the PIN provided by the applicant as well as the data extracted from the phone by using the PIN.
The lawfulness of seizure and retention of the applicant’s phone
Having reached this conclusion, it is strictly unnecessary to address the other bases upon which the applicant contended that the contents of the phone ought to be excluded: irrespective of whether those grounds were upheld, the result would be the same.
However, I add that, had it been necessary, I would have found that the retention of the applicant’s phone after police ascertained his identity was unlawful. My reasons, in summary form, for this alternative conclusion follow.
On the existing state of authority, there is some debate as to whether the lawfulness of the seizure and/or retention of the applicant’s phone is to be determined by reference to s 68 of the SOA or by the common law criteria for seizure and retention of an article from a third party set out in Ghani v Jones [1970] 1 QB 693.
In Ghani v Jones [1970] 1 QB 693 at 708-709, Lord Denning identified the circumstances in which a police officer may seize an item without warrant or effecting an arrest:
What is the principle underlying these instances? We have to consider, on the one hand, the freedom on the individual. His privacy and his possessions are not to be invaded except for the most compelling reasons. On the other hand, we have to consider the interest of society at large in finding out wrongdoers and repressing crime. Honest citizens should help the police and not hinder them in their efforts to track down criminals. Balancing these interests, I should have thought that, in order to justify the taking of an article, when no man has been arrested or charged, these requisites must be satisfied:
First: The police officers must have reasonable grounds for believing that a serious offence has been committed—so serious that it is of the first importance that the offenders should be caught and brought to justice.
Second: The police officers must have reasonable grounds for believing that the article in question is either the fruit of the crime (as in the case of stolen goods) or is the instrument by which the crime was committed (as in the case of the axe used by the murderer) or is material evidence to prove the commission of the crime (as in the case of the car used by a bank raider or the saucer used by a train robber).
Third: The police officers must have reasonable grounds to believe that the person in possession of it has himself committed the crime, or is implicated in it, or is accessory to it, or at any rate his refusal must be quite unreasonable.
Fourth: The police must not keep the article, nor prevent its removal, for any longer than is reasonably necessary to complete their investigations or preserve it for evidence. If a copy will suffice, it should be made and the original returned. As soon as the case is over, or it is decided not to go on with it, the article should be returned.
Finally: The lawfulness of the conduct of the police must be judged at the time, and not by what happens afterwards.
The power Detective Chadbourne purported to rely on to initially seize and subsequently retain the applicant’s phone was s 68 of the SOA. That section provides:
68—Power to search suspected vehicles, vessels, and persons
(1)A police officer may do any or all of the following things, namely, stop, search and detain—
(a)a vehicle or vessel in or upon which there is reasonable cause to suspect              that—
(i)    there are stolen goods; or
(ii)     there is an object, possession of which constitutes an offence; or
(iii)    there is evidence of the commission of an indictable offence;
(b)     a person who is reasonably suspected of having, on or about his or her person—
(i)    stolen goods; or
(ii)     an object, possession of which constitutes an offence; or
(iii)    evidence of the commission of an indictable offence.
(2)In this section— stolen goods includes goods obtained by the commission of an offence.
It can be seen from a comparison of the Ghani v Jones criteria and the terms of s 68 that, in some respects, Ghani v Jones imposes a more demanding test for the seizure and retention of items than s 68. That follows because the Ghani v Jones principles require, relevantly, the seizing officer to have reasonable grounds for believing that an article is material evidence to prove the commission of a crime or that a refusal by a third party to hand over an item is otherwise unreasonable.
Further, once an article is seized, Ghani v Jones provides that it may be retained for no longer than is reasonably necessary for police to complete investigations or preserve the article for evidence.
Contrastingly, if the source of power to seize and retain the applicant’s phone was s 68 of the SOA - which has been said to supplant and supplement the common law[122] authority to retain evidence recognised in R v Lushington; ex parte Otto [1894] 1 QB 420 - the relevant inquiry is whether, at the time of seizure, it was reasonable to suspect that the phone might afford evidence of LS’ offending and, after discovery of the applicant’s identity, whether the phone may have been evidence of a crime.
[122] Middlin-Hannah v The Queen (2020) 137 SASR 366, [134] (Livesey J).
In Middlin-Hannah v The Queen (2020) 137 SASR 366, different views were expressed about the scope of s 68 and the status of the Ghani v Jones principles. However, as will be seen, my conclusion would have been the same irrespective of whether Ghani v Jones or s 68 and R v Lushington are thought to be the source of power to retain items considered to afford evidence of an offence.
Remaining with s 68 of the SOA, the meaning of the phrase ‘reasonable to suspect’ or ‘reasonable cause to suspect’ – a close analogue for the formulation in s 68 of ‘reasonably suspected’ - is well-settled. In the context of unlawful searches, it has been said that a suspicion that a fact exists is less certain than a belief in the existence of that fact.[123] As the Full Court of the Supreme Court explained in R v Nguyen (2013) SASR 432 at [21]-[22]:
A suspicion that a fact exists is less certain than a belief in the existence of that fact. A belief is held on information which is accepted as reliable and implies a reasonable satisfaction that the fact is at least more likely to be true than any other alternative fact or facts. On the other hand, a suspicion that a fact exists, in the context of an investigation of the truth of that fact, is a working hypothesis for which there is some supporting material. There must be a rational connection between the supporting material and the suspicion. Mere curiosity, speculation or “idle wondering” about the existence of the fact is not the same as a suspicion that it exists.
[123] George v Rockett (1990) 170 CLR 104, 115-116.

The purpose of the qualifier ‘reasonable’ in s 68 of the SOA may be thought to be the same as in s 67 of the SOA: it is designed to prevent incredulous, gullible, naïve and artificially held subjective suspicions from empowering police officers to execute powers to stop, search, seize or retain items, because of the significant intrusion that such exercises of power have upon civil liberties. A ‘reasonable’ suspicion is often contrasted with a suspicion that is the product of or involves little more than ‘mere idle wondering’. A ‘reasonable’ suspicion is one founded on ‘more than a reason to consider or look into the possibility of the existence’ of a particular fact – in this case, that there was evidence of child exploitation offending on the applicant’s phone. If s 68 applied to the retention of the phone, for Detective Chadbourne’s suspicion at the time of seizing or retaining the phone to be a reasonable one, there had to be something more than a tenuous, even if rational, connection between the information she had available to her and the working hypothesis that there was evidence of child exploitation offending on the phone.[124]
[124] Queensland Bacon Pty Ltd v Rees (1966) 115 CLR 266, 303.
Whether a subjectively held suspicion is a reasonably held suspicion requires an assessment of whether the information available to the relevant police officer at the time the power of search, seizure or retention is engaged would ‘rationally produce a suspicion in the mind of…a person thinking reasonably about that information’.[125] In Bae and Koo v The Queen [2020] SASCFC 7 at [76], the test in relation to a search was expressed in the following slightly different, but conceptually aligned terms, namely, whether a ‘reasonable person in possession of the same information as the police officer would entertain the same suspicion’.[126]
[125] R v Nguyen (2013) 117 SASR 432, [22].
[126] See also George v Rockett (1990) 170 CLR 104, 112; Prior v Mole (2017) 91 ALJR 441, [4].
Relevant considerations when examining the reasonableness of a suspicion based upon information available to a police officer when a power of the kind conferred by s 68 is deployed include:
·The nature and extent of the information.
·The particularity or generality of the information.[127]
·The source of the information.
·The ostensible reliability and credibility of the information.
·The currency of the information.
·The nature and duration of the illicit activity to which the information relates.
[127] See, eg, McHugh v The Queen [2022] SASCA 5, [9]-[10].
I accept that when Detective Chadbourne asked the applicant to produce his identification and his phone, that she did so essentially simultaneously and on the assumption that the applicant was LS. This aspect of Detective Chadbourne’s evidence was not seriously challenged.
The applicant produced his identification first and his phone shortly thereafter. Detective Chadbourne quickly reviewed the identification and discerned that the applicant was not LS, but by that time, for the purpose of Ghani v Jones or s 68 of the SOA, the applicant had already been stopped and searched – the search constituted by what was essentially the demand made of him to produce his mobile phone.
As the initial search and seizure of the phone took place on the basis that Detective Chadbourne believed the applicant to be LS, it could not be said to involve any illegality. The information that police had about LS supplied a more than adequate basis to reasonably believe (Ghani v Jones) or suspect (s 68) that a search of him might afford evidence of the commission of an offence.
Thereafter, however, the situation changed quite significantly once the police ascertained the applicant’s true identity. It is clear that the detectives suspected that the applicant’s phone might afford evidence of the commission of the LS offending. However, to my mind that suspicion was not objectively reasonable.
At that point, police were dealing with a person who had no identified connection to their investigation. There was no information suggesting that the applicant had been in receipt of the child exploitation material disseminated by LS or that he was complicit in its production or dissemination or present at the house at the time of any such activity. Nor did police have information that LS was in fact disseminating the material to a broader audience.
I accept, as my earlier findings indicate, that after producing his phone, the applicant provided information to Detective Chadbourne to the effect that he had been staying at the house for a short period and was in a relationship with NB. The applicant had, of course, also been seen leaving the house shortly before he was intercepted.
However, I do not accept that, based on this information, it was either (1) reasonable to suspect that the applicant’s phone might afford evidence of the commission of an offence by LS (s 68); (2) that the phone may afford evidence of the commission of an offence by LS (Lushington); or (3) that the phone was retained for no longer than was reasonable or necessary for police to complete their investigation or preserve the phone as evidence (Ghani v Jones).
In short, any suspicion that the phone might afford evidence of an offence committed by LS was little more than speculation, idle wondering or mere curiosity. Equally, once the applicant’s identity had been discovered, and based on the information then available to police, it was unreasonable to retain the phone because it could not have been thought necessary to do so for investigative purposes: the phone could not rationally be thought to be a potential source of evidence against LS.
In my view, it was speculative to think that because the applicant had come from the house; had been staying at the house for a short period of time; and was in a relationship with NB, that there might have been evidence of the commission of an offence by LS on his personal mobile phone.
The situation would have been very different if police had any information to suggest that LS had used the applicant’s phone or even had access to the applicant’s phone throughout the relevant period. They had no such information.
I find then that the retention of the phone was unlawful,[128] even if the initial seizure of the phone was not unlawful because of the misapprehension as to the applicant’s identity. If an article comes into the possession of police based on a misapprehension about the identity of the possessor of the article which is subsequently dispelled, I doubt that the fact that the article may have been lawfully seized because of the misapprehension allows one to ignore the state of affairs once the misapprehension is resolved. That is to say, once the applicant’s identity was confirmed, the lawfulness of the retention of the phone had to be considered on very different factual premises.
[128] I note the concession of the prosecution that, if Ghani v Jones is applicable, a finding that the retention of the phone was unlawful is open: Prosecution’s Written Submissions, [44].
In this respect, I am satisfied that the illegality resulted directly in the obtaining of the applicant’s phone and the subsequent interrogation of the phone was causally linked with the unauthorised retention. It follows that the nexus between the unlawful or improper conduct and the obtaining of evidence required to enliven the Bunning v Cross discretion is established.
I accept that there is some force in the submission advanced by the prosecution that, if I were to find the retention of the phone was unlawful, I should decline to exclude the evidence because of the difficulty in discerning the source and scope of any power of retention in the unusual circumstances of this case. Conversely, I think a moment of thought being given to the circumstances that were known to the police after the applicant’s identity was ascertained would have revealed a serious question about the power of police to retain the phone. In any event, Detective Chadbourne was clear in her mind that s 68 provided the source of power to retain the phone and, as I have said, the test provided by s 68 is, it seems to me, less demanding than that provided by Ghani v Jones.
The decision to retain the phone reflects what appeared to be described as a standing policy that any electronic devices connected with a property regarded as a crime scene ought to be seized and interrogated irrespective of in whose possession or control those devices were and their suspected involvement in the offending being investigated and irrespective of the degree of connection the possessor of the device has with the property.[129] I note further the evidence of Detective Chadbourne that she would have seized the applicant’s phone even if she knew he was not LS to begin with and even if he provided no further information about his connection to the house.
[129] I do not overlook that, according to the agreed facts, and despite the evidence of Detective Chadbourne to the contrary, the mobile phone of NB was not seized or reviewed.
If I am correct that the actual information available to Detective Chadbourne when the decision was made to retain the phone was insufficient, this evidence would demonstrate a substantial misunderstanding of the circumstances in which a power such as that conferred by s 68 can be exercised. Similarly, Detective Dalton’s evidence that although there was no information to indicate there might be evidence on the applicant’s phone it was nonetheless appropriate to seize it because ‘you have to investigate everybody at the premises’, with the implication that it is therefore appropriate to seize the device of any person at the premises without more, is cause for some concern. So too is the evidence of Detective Dunworth that it was appropriate to seize the applicant’s phone even though she was of the understanding he did not live at the property. The evidence tends to indicate a far too undemanding view of the test of ‘reasonable suspicion’.
In making this observation, I acknowledge that interactions such as the one police engaged in on 29 June 2022 will often be fast moving and dynamic and it can be difficult to balance on a fine edge whether there is or is not a sufficient basis to seize and retain an article. There is considerable force in the proposition that offending of the kind police were investigating requires a robust and vigorous use of police powers. However, the test for searching, seizing and retaining items does not change depending on the nature of the offence being investigated. Accordingly, I am of the view that, even in the somewhat fluid circumstances facing police on 29 June, the asserted suspicion that the applicant’s phone might afford evidence of the commission of an offence so as to justify its ongoing retention was an unreasonable one.
Whilst there will be many situations in which police investigating offences of the kind under consideration here will be justified in seizing, retaining and searching electronic devices found at crime scenes or on people connected with crime scenes, a fact sensitive inquiry must always be conducted. In this case, that fact sensitive inquiry leads to the conclusion that the retention of the applicant’s phone was arbitrary and based on a mere curiosity or speculation given the absence of any information reasonably capable of supporting the idea that LS had access to or had used the applicant’s phone.
Despite the cogency of the evidence obtained in consequence of the unlawful or improper conduct and the seriousness of the charge the applicant now faces, declining to exclude the evidence of the phone extraction would give the appearance of judicial acquiescence in the wrongful use of seriously intrusive, coercive powers.
It is not necessary, and I do not propose, to consider the applicant’s further argument that he was under de-facto arrest after he was intercepted by police. However, my acceptance of Detective Patterson’s evidence that the applicant was essentially told that he was free to wander around as he pleased, would have provided a substantial obstacle to any conclusion that the applicant was under de-facto arrest.
Conclusion
The application is allowed in part.
I would admit the evidence of the applicant’s answers to police questions concerning his identity; where he was living and relationship with NB.
I would exclude evidence of the provision by the applicant of his PIN and the data extraction from the applicant’s phone having regard to the failure to caution or warn prior to asking for his PIN and because of the unlawful retention of his phone after his identity was discovered.