A US marine has been jailed for 21 months after he pleaded guilty to the aggravated assault of an Iraqi man who was killed in the town of Hamdania in April.
Lance Corporal Jerry Shumate also admitted conspiracy to obstruct justice.
Eight men were originally charged with kidnapping Hashim Ibrahim Awad and trying to cover up his killing.
In return for his guilty pleas, the government dismissed other charges against Shumate, including murder, kidnapping, assault and conspiracy.
Three other servicemen have already pleaded guilty in the case. Four more defendants still face courts martial.
During his testimony at Camp Pendleton in California, Shumate said that the squad had been looking for Iraqis planting bombs when all eight men agreed a plan to kill a known fighter.
The shooting was one in a series of incidents in which the conduct of American troops in Iraq came under scrutiny
Send us your views
Four of the squad left to abduct him, Shumate said. When they returned with a prisoner, Shumate said he was "told to fire" by the squad leader.
He learned later that it was Awad, whom prosecutors have described as a disabled father of 11.
The eight men are also accused of planting a gun and a shovel next to the body to make him look like he was planting bombs. The shooting was one in a series of incidents in which the conduct of American troops in Iraq came under scrutiny.
Other US marines based at Camp Pendleton are under investigation over a separate incident in November 2005 in which 24 civilians were killed in the Iraqi town of Haditha.