A murder–suicide is an act where an individual intentionally kills one or more people, before or while also killing themselves. The suicide may be in response to the guilt one feels for the murder, or to avoid potential punishments, such as imprisonment. Some forms of murder also inherently entail suicide; such as suicide attacks, or when the operator of an aircraft with passengers deliberately crashes it.
Many perpetrators of spree killings, such as mass shootings and school shootings, either end their own lives afterwards, or intend to be killed by police. Some cases of religiously motivated mass suicides have also involved murder. All categorization amounts to forming somewhat arbitrary distinctions where relating to intention in the case of psychosis, where the intention(s) is/are more likely than not to be irrational. Ascertaining the legal intention (mens rea) is inapplicable to cases properly categorized as insanity.