Where an accused concedes the reliability of DNA evidence on appeal, the only remaining avenue to challenge conviction is to establish a reasonable possibility of contamination or an alternative hypothesis consistent with innocence; the jury is entitled to accept crime scene officer evidence about adherence to anti-contamination protocols. DNA evidence from cigarette butts found in incriminating circumstances near a crime scene can be sufficient on its own to support conviction, even without DNA on items found inside the crime scene. Trial judges are not required by s 61 of the Jury Directions Act 2015 (Vic) to direct juries that specific items of evidence must be proved beyond reasonable doubt, though they may do so as a matter of prudence where the evidence is critical to the prosecution case.
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