McGrath v The Queen

This matter came before the High Court of Australia on an application for special leave to appeal. The applicant, who had been convicted of wilful murder, sought to challenge the decision of the Court of Criminal Appeal of Western Australia. The applicant's conviction arose from a series of killings that occurred at the same time, during which he also committed three other killings for which he was found not guilty by reason of insanity. The central dispute concerned the timing of the applicant's descent into insanity, specifically whether the Court of Criminal Appeal erred in its assessment of expert psychiatric evidence regarding this transition.

The legal issue before the High Court was whether the Court of Criminal Appeal had made an error in its determination that the applicant was sane until after he assaulted his wife, and that the applicant's transition to insanity occurred at some point after that assault. The applicant contended that the Court of Criminal Appeal's conclusion was not supported by the evidence, particularly the cross-examination of Dr. Rollo, a key psychiatric expert. The applicant argued that the interests of justice warranted the grant of special leave to appeal to address this alleged error in the appellate process.

The applicant's argument focused on specific passages from the transcript of Dr. Rollo's evidence. During cross-examination by the Crown prosecutor, Dr. Rollo indicated it was "possible that he could have been regarded as in control" at the time of the assault on his wife, but expressed uncertainty. However, during re-examination by the defence, Dr. Rollo stated that, having heard the cross-examination, he would be inclined to place the change-over point from sanity to insanity "a little further back" than the shooting of Craig, acknowledging it was possible the applicant was still responding to reality factors at the time he hit his wife, but he "cannot be precise." Dr. Rollo ultimately stated he found it "impossible to put a precise time" when the applicant became insane, though he saw him as "clearly insane" at one point in prison. The applicant argued that the Court of Criminal Appeal had misinterpreted or misapplied this evidence, failing to recognise the ambiguity and the expert's concession that the applicant might have lost capacity to reason earlier than previously suggested.