When one person intentionally kills another without legal justification or excuse, the crime is called murder. The clearest example of this is a case where one person deliberately kills another because of hatred, envy, or greed. But there are also situations where a killing is considered murder even when no specific intent to kill exists. For example, a person who accidentally kills someone while committing a robbery is guilty of murder. The fact that the person is committing a serious crime indicates that he or she has a reckless disregard for human life and safety. This takes the place of intent to kill. The penalty for murder is a long prison sentence or death. But many national, state, and provincial governments have done away with the death penalty.

A killing that has legal justification is called justifiable homicide. For example, a killing in self-defense would be a justifiable homicide. The law regards a purely accidental killing as an excusable homicide. For example, if a pedestrian steps in front of a carefully driven automobile and is killed, the accident would be considered an excusable homicide. When a person in a fit of anger intentionally kills another person after the victim has provoked the attack, the killing is called voluntary manslaughter. When a persons death results from reckless driving or other extreme negligence on the part of the killer, the offense is called involuntary manslaughter. The penalties in most cases of manslaughter are less severe than those for murder.