An active shooter is an individual actively engaged in killing or attempting to kill in a confined and populated area using firearms, with no apparent method in selecting victims. Preparations for an active shooter situation can range from little planning to extensive pre-planning involving procuring weapons, conducting surveillance, setting booby traps, and blocking exits to maximize casualties. The most common victims are those with a current or former workplace relationship to the attacker, though no group is safe, and the most likely targets are schools, outdoor areas, and businesses.