The killer wore Afghan army uniform and may have lured the US soldiers into an ambush. The US Department of Defense said the three Americans died of wounds suffered “when they encountered an insurgent who detonated a suicide vest" in Kunar province. They were identified as Army Command Sgt. Maj. Kevin J. Griffith, the senior enlisted soldier of the 4th Brigade Combat Team, 4th Infantry Division, from Fort Carson, Colorado; Army Maj. Thomas E. Kennedy, 35, of West Point, New York; and Air Force Maj. Walter D. Gray, 38, of Conyers, Georgia.