R v Humphrey - [1999] SASC 67

R v HUMPHREY
[1999] SASC 67

Criminal (Reasons for Ruling)
Bleby J

The accused was charged with the murder of Eugene Charles McLean at Lyrup Flats, in the South Australian Riverland, on 23 October 1997. There were no eye witnesses to the murder, and one of the issues in the case was whether the Crown could prove that it was the accused who killed McLean. What appeared to be blood stains or spots, one on the upper toe area of the left boot being worn by the accused at the time of his arrest (marked PWH4.A), and one from his jeans (marked PWH6.D), were submitted for DNA analysis by Ms Williams at the South Australian Forensic Science Centre. In the declaration submitted by Ms Williams she expressed the opinion that in respect of both spots the accused was excluded as the source of the DNA and the deceased was not.
In respect of the stain on the boot she further expressed the opinion that greater than 99.99% of the population would be excluded and that the statistical likelihood of that profile being repeated in the general population was less than one in ten thousand. In respect of the sample from the jeans, approximately 99.8% of the population would be excluded as the source of the blood stain.
Before the empanelling of a jury the defendant sought an order that that “frequency” evidence of Ms Williams was inadmissible unless it were proved that the data base from which the frequency evidence was derived was an appropriate one and unless it were proved that there was an absence of dependence between the alleles from which the frequency evidence was derived.
In order to resolve the question of admissibility I heard evidence on the voir dire from Ms Williams, a forensic scientist whose qualifications and experience include molecular biology, and Associate Professor Chaseling, an Associate Professor in Applied Statistics at Griffith University, both called by the prosecution. I also heard evidence from Dr Atchison, Manager, Molecular Biology, Victorian Institute of Forensic Medicine, part of the Department of Forensic Medicine at Monash University.
After hearing argument as to the admissibility of the frequency evidence I ruled that it was admissible provided that (if such matters were not otherwise agreed) evidence was also led from which the jury could determine the appropriateness or otherwise of the data base or bases used by Ms Williams, in respect of such matters as size, representation of the population, lack of dependency between and within particular loci and any matters which might affect the validity or weight of the frequency evidence. I indicated at the time that I would publish reasons for that ruling, and these are those reasons.
Deoxyribonucleic acid, or DNA, is contained in the chromosomes in the nucleus of most cells in the human body, and contains the code for each of a person’s characteristics or that person’s genetic makeup. The testing in this case was by means of the polymerase chain reaction (PCR) technique which…

Grounds of appeal

[14] The appellant contends that the primary judge erred in finding that the respondent had discharged the onus of establishing the matters required under the relevant provision.

[15] It was submitted that his Honour failed to give adequate weight to the evidence of the second witness, and that the findings of fact were not reasonably open on the material before the Court.

[16] The respondent, for its part, submits that no error is disclosed, and that the conclusions reached were well within the range of outcomes available to the primary judge.

Consideration

[17] It is convenient to deal first with the question of construction, as the resolution of that issue informs the remaining grounds advanced by the appellant.

[18] For the reasons that follow, we are of the view that the appeal should be allowed in part and the matter remitted for further determination.

Continue reading R v Humphrey

Details

AGLC: R v Humphrey [1999] SASC 67
Case: [1999] SASC 67
Decision Date: 25 February 1999

CaseChat Overview and Summary

In the Supreme Court of South Australia, Bleby J considered the admissibility of DNA frequency evidence in the case of R v Humphrey. The accused was charged with the murder of Eugene Charles McLean, and the prosecution sought to rely on DNA evidence to link the accused to the crime scene. Ms Williams, a forensic scientist, provided a declaration stating that the accused was excluded as the source of blood stains found on his clothing, with a statistical likelihood of the profile being repeated in the general population being less than one in ten thousand. The defence challenged the admissibility of the frequency evidence, arguing that the data base used by Ms Williams was not representative of the relevant population and that there was a lack of dependency between the alleles. The court heard evidence from experts on both sides and ruled that the frequency evidence was admissible provided that evidence was also led from which the jury could determine the appropriateness or otherwise of the data base used. The court held that it was not for the trial judge to determine the appropriate population for the data base or to assess the representative nature of the sample within the data base. Instead, these matters were to be determined by the jury, properly directed. The court added a proviso that evidence should also be led from which the jury could determine the appropriateness or otherwise of the data bases used, to avoid the risk of the jury being overawed by the scientific garb in which the evidence was presented without an understanding of its foundation.

Orders