A murder–suicide is an act in which an individual kills one or more other persons immediately before or at the same time as killing oneself. The combination of murder and suicide can take various forms, often linked to the first form: Suicide-lawful killing has three conceivable forms: * To murder one's assailant through proportionate self-defense killing oneself in the process; * Lawful killing to prevent an individual from causing harm to others, in so doing killing oneself; * Lawful killing indirectly resulting in or contributing to suicide.