Johanne St-Gelais

The appellant appealed his convictions for first degree murder and three counts of attempted murder.

The issues on appeal included whether the trial judge erred in not putting the defence of mental disorder automatism to the jury, in summarizing expert testimony, and in charging the jury on the mens rea for criminal harassment.

The Supreme Court of Canada dismissed the appeal from the bench, adopting the reasons of the majority of the Quebec Court of Appeal.

The appellants were convicted of first degree murder.

Duguay later pleaded guilty to manslaughter after a new trial was ordered.

A public inquiry subsequently revealed that the Crown and police failed to disclose significant relevant evidence to the defence at the original trial.

The Supreme Court of Canada held that the Crown's failure to disclose this evidence infringed the appellants' right to make full answer and defence under s. 7 of the Charter.

The Court clarified the test from Dixon for assessing the impact of non-disclosure on the verdict and trial fairness, and adapted it for cases involving guilty pleas.

Taillefer's conviction was quashed and a new trial ordered.

Duguay was permitted to withdraw his guilty plea, and a stay of proceedings was entered due to the significant time he had already served.