A Marine pleaded guilty Monday to aggravated assault and conspiracy to obstruct justice in the case of an Iraqi civilian who other servicemen said was kidnapped and killed by members of the squad.

Lance Cpl. Tyler A. Jackson, 23, entered those pleas and others through his attorney Thomas Watt at a military court hearing. Jackson pleaded not guilty to murder, kidnapping, larceny, housebreaking and another charge of conspiracy.

Jackson was the third serviceman to plead guilty to reduced charges in return for his testimony in the case, in which seven Camp Pendleton-based Marines and a Navy corpsman were charged with murdering 52-year-old Hashim Ibrahim Awad.

Jackson, who has been in military prison since May, spoke only to confirm his identity and attorneys' names and say he understood his rights.

The sentencing guidelines for the counts Jackson pleaded guilty to were not immediately clear.

Last month, Pfc. John Jodka III pleaded guilty to assault and conspiracy to obstruct justice in the incident.

The first to make a deal was Petty Officer 3rd Class Melson J. Bacos, a Navy corpsman on patrol with the Marines. He pleaded guilty to kidnapping and conspiracy.

Members of the squad abducted Awad after their plot to kidnap and kill a known insurgent failed, according to testimony from Bacos and Jodka. The victim was a former policeman and father of 11.

Awad was shot after being dragged to a hole several hundred yards from his house, Bacos and Jodka said. A shovel and AK-47 were placed near the body to make it appear Awad was an insurgent planting a roadside bomb, both defendants said.

Both Jodka and Bacos singled out their squad leader, Sgt. Lawrence G. Hutchins, as hatching a plan to kidnap an insurgent. Hutchins' attorney, Rich Brannon, has said he did not believe Hutchins did anything wrong.

Jackson joined the Marines in March 2005 and was on his first combat tour.

His father declined to comment. A Web site set up by Jackson's family to raise money for his defense said Jackson was innocent.

"To send these men to war to do a job and then imprison them for doing it is absurd," the Web site states.

"Why are they being subjected to less rights and freedom of movement than the very terrorists they put their lives on the line to protect the world from?" the site states.