By Marty Graham CAMP PENDLETON, Calif., March 1 (Reuters) - A U.S. Marine accused of helping to kidnap and kill a 52-year-old Iraqi grandfather in the town of Hamdania was arraigned on Thursday on six charges, including premeditated murder and conspiracy. It was the second arraignment for 25-year-old Lance Cpl. Trent Thomas, who did not enter a plea. He had made a plea bargain with prosecutors in January and entered a guilty plea, but withdrew the plea in February. Thomas plans to fight the charges by arguing he was following orders issued by another of the eight defendants in the killing, defense lawyer Victor Kelly said. Seven Marines and a U.S. Navy medic have been charged in the April 2006 killing of Hashim Ibrahim Awad, a disabled police officer. Awad was dragged from his home, placed in a bomb crater with a stolen shovel and rifle and then shot to death as the troops faked the sound of a firefight, according to testimony by other defendants. The Hamdania killing is one of several incidents that have embarrassed U.S. troops in Iraq. Four Marines have been charged with murder and four others with dereliction of duty in the Nov. 19, 2005 killing of 24 Iraqi civilians in the town of Haditha in November 2005. The killing of Awad was initially reported as a firefight with an insurgent caught planting a bomb. That came under scrutiny when Awad's family complained to their village sheikh, who brought the complaint to the Marine Corps. Five of the eight servicemen charged have pleaded guilty and received reduced sentences in exchange for cooperating with prosecutors. Lawyers for Thomas moved on Thursday to reserve his right to enter a plea while arguing procedural motions expected to end Friday.