Murder is the unlawful killing of another human without justification or valid excuse committed with the necessary intention as defined by the law in a specific jurisdiction. This state of mind may, depending upon the jurisdiction, distinguish murder from other forms of unlawful homicide, such as manslaughter. Manslaughter is killing committed in the absence of malice, such as in the case of voluntary manslaughter brought about by reasonable provocation, or diminished capacity. Involuntary manslaughter, where it is recognized, is a killing that lacks all but the most attenuated guilty intent, recklessness.

Life imprisonment is any sentence of imprisonment for a crime under which convicted criminals are to remain in prison for the rest of their natural lives. Crimes that warrant life imprisonment are extremely serious and usually violent. Examples of these crimes are murder, torture, terrorism, child abuse resulting in death, rape, espionage, treason, illegal drug trade, human trafficking, severe fraud and financial crimes, aggravated property damage, arson, hate crime, kidnapping, burglary, robbery, piracy, aircraft hijacking, and genocide.