The appellant and a co-accused were originally tried jointly and convicted of first degree murder.
A new trial was ordered, but prior to the second trial, the co-accused pleaded guilty to second degree murder and accepted a statement of facts indicating his footprints were at the scene.
At the appellant's second trial, the defence intended to call a footprint expert who had testified at the first trial that the footprints were not the co-accused's.
The trial judge permitted the Crown to cross-examine the defence expert on whether the co-accused's guilty plea and admission would change his opinion.
The defence consequently did not call the expert, and the appellant was convicted.
The Supreme Court of Canada allowed the appeal and ordered a new trial, holding that an expert cannot be cross-examined on facts that are not and will become part of the admissible evidence.
