The appellant challenged a sexual assault conviction where forensic DNA source evidence was treated as probative despite defence evidence that it lacked scientific foundation.
The Court held that the trial judge applied materially different levels of scrutiny to the Crown and defence experts, accepting the Crown expert evidence at face value while intensely scrutinizing the defence expert.
That asymmetry was unwarranted and tended to shift the burden of proof.
The conviction was quashed and a new trial was ordered, with admissibility of the impugned DNA source opinion to be determined at any retrial if tendered.
