Nirvana, a military working dog, is held back from attacking the “suspect” by her handler, Staff Sgt. Monica Bizallion, 11th Security Forces Support Squadron military working dog handler, at Joint Base Andrews, Md., Mar. 12, 2015. Team Andrews security forces officers utilize more than 30 MWDs to help protect the base, residents and flight line. (U.S. Air Force photo/Airman 1st Class Joshua R. M. Dewberry)