Active Shooter Training Exercise
U.S. Air Force Airman 1st Class Lee Jackson (left) and Senior Airman Joshua Ridgley, 161st Security Forces Squadron members, clear a room during a simulated active shooter exercise at the 161st Air Refueling Guard base, Phoenix, June 4, 2011. This exercise brings together members of the Air National Guard, the Phoenix Police Department, the Federal Aviation Administration and the Transportation Security Agency in order to improve interagency communication. (U.S. Air Force photo by Staff Sgt. Courtney Enos/Released)