The appellant was convicted of three counts of first degree murder for being a party, with her spouse, to the murder of their three children as part of a murder-suicide pact.
She argued the trial judge erred in not putting the defence of abandonment to the jury as an alternative to her primary defence of absence of mens rea.
The Supreme Court held there is no cardinal rule against putting incompatible defences to a jury, but the defence of abandonment did not meet the air of reality test because the appellant, who had supplied the murder weapon, failed to take reasonable steps proportional to her participation to neutralize its effects or prevent the offence.
The Court reformulated the test for abandonment under s. 21(1) of the Criminal Code to include a fourth element requiring proportional neutralizing or preventative steps.