R v Martineau, [1990] 2 SCR 633 is a leading Supreme Court of Canada case on the mens rea requirement for murder.

One evening in February 1985, Patrick Tremblay and 15-year-old Mr. Martineau set out to rob a trailer owned by the McLean family in Valleyview, Alberta.

Section 213(a) defined culpable homicide as murder if a person causes the death of another human while committing specific indictable offences, such as breaking and entering.

One could be charged with murder under section 213(a) despite having neither an intent to kill nor the subjective knowledge that death might ensue from one's actions.

Furthermore, the appropriate level of mens rea should be correlated to the severity of the punishment and the social stigma stemming from conviction.