Situations involving active shooters in schools have increased in recent years. Researchers define an active shooter incident as an occurrence where one or more individuals take part in an ongoing, random, or systematic shooting spree with the objective of multiple or mass murders. Evidence suggests that mental instability, social isolation, a self-perception of catastrophic loss, and access to weapons play a role in the identification of the shooter in a school shooting incident. Describe and explain six characteristics common in these offenders.