MASS KILLING: three or more individuals killed in a single incident not including the shooter MASS SHOOTING: three or more individuals injured and/or killed in a single incident not including the shooter MULTIPLE LOCATIONS: incidents where an active shooting attack occurred at more than one location PREDATORY BEHAVIOR: incidents when a perpetrator considers, plans, and prepares for the act of violence; they are preceded by observable warning sign behaviors that, if recognized and reported, can provide opportunities for disruption SECURITY INTERVENTION: instances where security personnel intervened or attempted to intervene to end an active shooter incident
