Lance Cpl. Tyler Jackson, 23, of Tracy, California, said he agreed to go along with the plan to kill an Iraqi man they believed was a terrorist during a patrol near the village of Hamdania.

"Everyone there verbally agreed. Not much more was said," Jackson told a court-martial at the Camp Pendleton Marine Corps Base north of San Diego.

Jackson pleaded guilty to charges of aggravated assault and conspiracy to obstruct justice. The judge, Marine Lt. Col. Joseph Lisiecki, accepted the guilty pleas and set the sentencing hearing for November 16.

Jackson, who has been held in a military brig since late May, could face up to 15 years in prison.

Under a pretrial agreement with military prosecutors, he is expected to receive a lesser punishment in exchange for his cooperation and testimony against five other members of his squad charged in the death.

Jackson is the third member of the unit to plead guilty to charges related to the killing.

Unit members have testified the plan by squad leader Sgt. Lawrence Hutchins was to nab Saleh Gowad, whom they suspected participated in attacks against the Marines, including a roadside explosion that killed four members of their unit.

That night, four of the men grabbed not Gowad but another man in the village, tied him up, dragged him to a hole on a road, and then all eight of the men fired their weapons at the man, Jackson said.

Jackson said he went along with the plan to kill Gowad because he agreed with it.

According to his testimony, only later did Jackson realize that they had actually grabbed and killed another man, Hashim Ibrahim Awad, 52, a former Iraqi policeman.

Jackson said he too got in a line at the sergeant's behest and fired, but aimed above the man's head.

"I knew he was going to be shot. I didn't want to be the one doing it," he told the judge.

The eight men agreed to stick to the story that he was shot after getting into a firefight with the Marines, Jackson said.

"We would tell the story that the man was digging an IED along the road," he said, referring to a bomb known as an improvised explosive device. If they were ever questioned, they would say "it was a good shot, a lawful engagement," he added.

Jackson is one of seven Marines and a sailor with a platoon belonging to 3rd Battalion, 5th Marine Regiment, an infantry unit based at Camp Pendleton, charged in the Iraqi's death.

In addition to the sailor, Jackson is the second Marine to plead guilty in the case.

The five others face charges including premeditated murder.