Case in Brief

A Case in Brief is a short summary of a written decision of the Court, drafted in plain language. These summaries are prepared by staff of the Supreme Court of Canada. They do not form part of the Court’s reasons for judgment and are not for use in legal proceedings.

R. v. B.F.

Case summary

The Supreme Court of Canada says that juries should only be asked to consider a theory if it is realistically supported by the evidence.

This case was about whether the trial judge gave the jury the instructions they needed to decide the case according to the law and the evidence. When a trial is heard by a jury, the judge must explain the law to the jurors and guide them on how to consider the evidence. Some instructions must always be given, like the elements of the offences. But instructions about an alternative theory are only needed if there is evidence that could realistically support that theory. This is the “air of reality” requirement. It means a theory must have at least a basic level of evidence behind it before the jury is asked to consider it.

The accused, her 19-month old child, and her mother were all found unconscious in their apartment after receiving dangerous doses of insulin. The accused and her mother fully recovered, but the child suffered life-altering injuries. The accused, who was a nurse, was charged with two counts of attempted murder and two counts of aggravated assault. Attempted murder means trying to kill someone but not succeeding. Aggravated assault is a very serious form of assault that causes major bodily harm. The Crown said the accused had both the motive and the opportunity to commit these crimes. It relied on evidence such as empty insulin pens and a handwritten letter found in the apartment.

At trial, the defence suggested that the mother might have injected herself with insulin, and that this could point to a suicide attempt rather than attempted murder. Helping someone take their own life (aiding suicide) is a different crime from attempted murder, and the accused was not charged with that offence. The trial judge did not give the jurors instructions related to aiding suicide. The Court of Appeal said the trial judge should have helped the jury understand the difference between attempted murder and aiding suicide, in light of the defence theory raised at trial. It ordered a new trial on the count involving the mother, but left in place the conviction for the offences against the child. Both the Crown and the accused appealed to the Supreme Court of Canada.

The Supreme Court allowed the Crown’s appeal, restored the accused’s conviction for attempted murder of her mother, and dismissed the accused’s appeal.

The judge’s instructions were complete and accurate.

Writing for a majority of judges of the Supreme Court, Justice O’Bonsawin said that the air of reality test helps ensure juries focus only on theories that have evidence behind them. A judge should not give instructions about a defence or alternative theory unless the evidence at trial could reasonably support it.

Justice O’Bonsawin explained that in this case, there was no evidence that the accused’s mother tried to take her own life. Because there was no evidence pointing to a suicide attempt, the trial judge was right to not instruct the jury on this theory. Justice O’Bonsawin also concluded there was no error in the trial judge’s instructions for the accused’s offences regarding her child.