150815-N-VC599-314 CHATTANOOGA, Tenn. (Aug. 15, 2015) - Secretary of Defense, the Hon. Ashton Carter, speaks during the memorial at McKenzie Arena at University of Tennessee Chattanooga. The event honored the four Marines and one Sailor who died in the Navy Operational Support Center Chattanooga shooting July 16. (U.S. Navy photo by Mass Communication Specialist 2nd Class Justin Wolpert/Released)