Criminal homicide may be classified as murder, manslaughter, or criminally negligent homicide. A person commits criminal homicide if he intentionally, knowingly, recklessly or with criminal negligence causes the death of another person. Homicides that are neither justifiable nor excusable are considered crimes.
Non-criminal homicides include killing in self-defense, an accidental death like a hunting accident or automobile collision without a violation of law like reckless driving, or carrying out a sentence of execution. An execution is an example of a justifiable homicide, which is an intentional killing done in accordance with legal obligation, or in circumstances where the law recognizes no wrong. Justifiable homicide may also include killings necessary to prevent a felony or to arrest a suspected felon, and killings in self-defense. In some states of the United States, one may lawfully kill in resisting the unlawful invasion of a home or real property.