The accused was charged with murder and raised the defence of insanity.
At trial, Crown psychiatrists testified that the accused was sane, having changed their initial opinions after misinterpreting a Supreme Court of Canada decision.
The trial judge instructed the jury that 'appreciating' and 'knowing' in s. 16(2) of the Criminal Code had the same meaning.
The accused was convicted, but the Court of Appeal set aside the conviction and found him not guilty by reason of insanity.
The Supreme Court of Canada dismissed the Crown's appeal, holding that 'appreciating' and 'knowing' have distinct meanings, and the jury was misdirected based on the experts' erroneous understanding of the law.
