Citation: R v KE [2019] NSWDC 349
Court: District Court of New South Wales
Date: 16 July 2019
Judge(s): Grant DCJ
Background
The accused faced a seven-count indictment. Counts 6 and 7 alleged that on 21 January 2018 the accused, a 30-year-old man in a de facto relationship with the complainant's mother, performed cunnilingus on the complainant, who was 14 years old, on two separate occasions at the family home in Claremont Meadows.
Following the alleged offending, the complainant underwent a sexual assault examination at Nepean Hospital. Swabs taken from her labia and vulva returned male DNA matching the accused's Y-STR and Y-filer profiles, with a frequency of approximately one in 750 unrelated males in the general population.
The defence applied to exclude that DNA evidence before trial. The accused had lived at the same property as the complainant and her mother for over four years.
Legal Issues
- Whether the DNA evidence was relevant under sections 55 and 56 of the Evidence Act 1995
- Whether, if relevant, the probative value of the DNA evidence was outweighed by the danger of unfair prejudice to the accused under section 137 of the Evidence Act 1995
Decision
Issue 1: Relevance
The court accepted the Crown's submission that the evidence should be assessed at its highest, acknowledging that the accused's DNA was present on swabs taken from the complainant's vulval area after the alleged offence. However, both expert witnesses agreed they were unable to determine whether the DNA was deposited through direct contact or by secondary transfer (at [23]). Because no expert could differentiate between those two explanations, the court found the evidence to be, at most, only marginally relevant (at [29]-[30]).
Issue 2: Probative value versus unfair prejudice under section 137
The court held that section 137 mandated exclusion where probative value is outweighed by the danger of unfair prejudice (at [32]). With both experts in complete agreement that neither direct nor secondary transfer was more likely than the other, the court found a jury would have no reasonable evidentiary basis for choosing between the two explanations (at [36]). A conclusion of guilty transference would therefore be wholly speculative (at [38]).
The court expressed particular concern about the "CSI effect," noting that jurors tend to place undue weight on DNA evidence and that the complexity of forensic DNA analysis would require careful jury directions (at [39]-[42]). The court found it unclear how any directions could adequately guard against misuse of the evidence in circumstances where the experts themselves were in agreement. The danger of unfair prejudice to the accused therefore outweighed whatever probative value the evidence possessed, and the evidence was excluded under section 137 (at [43]-[44]).
Orders Made
- DNA evidence excluded pursuant to section 137 of the Evidence Act 1995
Key Takeaways
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The District Court held that where two expert witnesses agree they cannot distinguish between direct DNA transfer and secondary DNA transfer, a jury has no reasonable basis for choosing between those explanations, and the evidence may be of only marginal relevance at best (at [29]-[30], [36]).
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Under section 137 of the Evidence Act 1995, a trial judge must exclude prosecution evidence where its probative value is outweighed by the danger of unfair prejudice. That mandatory evaluative exercise is not satisfied simply because DNA matching the accused is found on the complainant (at [32]).
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Where experts offer no competing opinions and both regard each possible explanation as equally open, a jury's conclusion of "guilty transference" would amount to impermissible speculation (at [38], [40]).
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The so-called "CSI effect," the tendency of juries to place disproportionate weight on DNA evidence, was treated by the court as a recognised and material consideration in the section 137 balancing exercise (at [42]).
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Decisions from the Victorian Court of Appeal in DPP (VIC) v Wise and the ACT Supreme Court in R v GZ were applied, confirming that DNA evidence recovered in proximity to an alleged sexual offence is not automatically admissible where innocent transference remains an equally open and unexplained possibility.
Legislation and Cases Referenced
Legislation
- Evidence Act 1995
Cases
- Adams v The Queen [2018] NSWCCA 303
- DPP (VIC) v Wise [2016] VSCA 173
- DPP v Paulino (No 3) [2017] VSC 345
- R v Beowulf [2019] ACTSC 64
- R v GZ [2015] ACTSC 229