Convicted under the UCMJ, article 118.
From Wikipedia
Less than two weeks later Mansur was ordered released due to military intelligence having insufficient evidence to hold him any longer. Behenna's platoon was tasked with the return of Mansur to town as soon as possible. On May 16, while returning the prisoner to a checkpoint as ordered, Behenna and his platoon stopped at a bridge in the northern oil refinery town of Baiji and, with the help of his Iraqi interpreter nicknamed "Harry", tried to question Mansur on the April 21st attacks. According to the interpreter, "Lieutenant Behenna started talking with Ali Mansur and Sergeant Warner followed them. Behenna and Warner started taking off Ali Mansur's clothes with their knives. They then cut his handcuffs." Behenna ordered the detainee to sit, the interpreter said, adding that Behenna seemed to be keen to get information from the detainee regarding the IED attack on U.S. troops in April. Behenna asked the detainee several times: "What do you know you have to tell me." "Ali Mansur said I will talk to you but Lieutenant Behenna pulled trigger and killed him," the interpreter said, speaking in English. "Before we started the patrol, Lieutenant Behenna told Ali Mansur 'I will kill you'. I thought Lieutenant Behenna was trying to scare him. I did not think he would go through (with it)," the interpreter added. "I was standing 10 metres (yards) back during the shooting -- I could see everything even if it was getting dark -- and Sergeant Warner was next to me." Warner then "took the grenade from his pocket, pulled the safety ring, walked around and put the grenade under Ali Mansur's head. "Then they hid his clothes, and Behenna and Warner went back." Two U.S. soldiers from the same battalion as the accused also testified against Warner. Corporal Cody Atkinson said that Behenna and Warner, armed with a grenade, took Mohammed out of the vehicle and under the bridge.[10]
