The State of Western Australia v Muller

The State of Western Australia brought a case against Muller, which was heard in the Supreme Court of Western Australia. The primary issue was the admissibility of DNA evidence and the competency of a mentally impaired witness's pre-trial evidence. The court needed to determine if the DNA evidence was relevant and if its prejudicial effect outweighed its probative value. Additionally, the court had to assess whether the mentally impaired witness was competent to give evidence, and if admitting the evidence would be unfair.

The court considered the relevance and probative value of the DNA evidence, weighing these against any prejudicial effect it might have. It was held that the probative value of the DNA evidence significantly outweighed any prejudicial effect. Regarding the mentally impaired witness, the court found that the witness was competent to give evidence and that the prejudicial effect of admitting the evidence did not outweigh its probative value. The court also concluded that admitting the evidence would not be unfair.

The court dismissed the application to exclude the DNA evidence and granted the application to lead the mentally impaired witness's pre-trial evidence. The trial proceeded with the DNA evidence and the witness's pre-trial testimony being admitted as part of the evidence.