When one person kills another directly, or has someone else kill that person, or the person is killed by the omission of another (that is, by their failure to act when the law requires them to act). It is not always a crime. Homicide can be:

  1. excusable - the result of a lawful act when no hurt was intended or from an act of self-defense;
  2. criminal - the result of any wrongful act without any excuse or justification in law; or
  3. justifiable - the result of an intentional but lawful act such as the execution of a death sentence by an agent of the law (can also apply to self-defense). (See also manslaughter, murder.)