U.S. Army Lt. Col. (Ret.) Dave Grossman, speaks to Team Beale members about Killology at the base theater, Beale Air Force Base, Calif., April 2, 2014. Grossman is an internationally recognized scholar, author, soldier and speaker who is one of the world's foremost experts in the field of human aggression and the roots of violence and violent crime. (U.S. Air Force photo by Senior Airman Allen Pollard/Released)