CAMP PENDLETON, Nov 21 (Reuters) - A U.S. Marine accused in the April killing of an Iraqi man in the town of Hamdania pleaded guilty on Tuesday to lesser charges as part of an agreement with prosecutors. Lance Cpl. Jerry Shumate, one of eight U.S. servicemen originally charged in the case, entered guilty pleas to aggravated assault and conspiracy to obstruct justice at a court martial hearing at Camp Pendleton, California. Under the agreement, more serious charges of murder, kidnapping and larceny will be dismissed against Shumate, 21, in exchange for his testimony. Four servicemen including Shumate have pleaded guilty so far in the case. Four defendants still face courts martial. They are accused of dragging 52-year-old Hashim Ibrahim Awad from him home, shooting him to death and covering up the crime by placing an assault rifle and a shovel next to the body to make it look like he was a roadside bomber. The shooting was one in a series of incidents in which the conduct of American troops in Iraq has hurt the country's image abroad. Other Camp Pendleton-based Marines are under investigation in a separate incident in November 2005 in which 24 civilians were killed in the Iraqi town of Haditha.