Mr. Strathdee was involved in a group assault at a downtown Edmonton apartment with at least four other men. Several victims were stabbed – one fatally so. He was charged with second degree murder, manslaughter, one count of break and enter, and three counts of aggravated assault.

At trial, he was acquitted of second-degree murder, manslaughter, and break and enter with intent. He was convicted on all three counts for aggravated assault as a party to the offence under section 21(2) of the Criminal Code, having been involved in a group assault.

With respect to the murder charge, the trial judge found as a fact that only one person could have caused the victim’s death and that no one else applied force to him. As such, under section 21(2)(a), Mr. Strathdee could not be found liable where the cause of death could have only been inflicted by one person. In that regard, an acquittal was entered.

The Crown appealed the acquittal on the homicide charge and the appellant cross-appealed his convictions for aggravated assault.

The Court of Appeal of Alberta found that the trial judge erred in her application of the law on joint participation, ultimately allowing the Crown’s appeal. The Court held that because of the judge’s finding of a group assault, she ought to have assessed Mr. Strathdee’s liability as a joint principal, and that the Crown was not required to prove that Mr. Strathdee personally applied force to the deceased. The acquittal was set aside and the Court substituted a conviction for manslaughter. Mr. Strathdee’s cross-appeal was dismissed.

Mr. Strathdee appealed his conviction for manslaughter as of right.

At issue before the Supreme Court of Canada is whether the trial judge erred in her application of the law of joint principals.