Excerpt - WASHINGTON (Reuters) - The head of the U.S. Marine Corps briefed Rep. John Murtha on the Haditha case after the vocal war critic publicly said Marines had killed innocent civilians in that Iraqi city, the Corps said on Thursday. A group of Marines, while suspected in the killing of 24 Iraqi civilians, has not been charged, and official results from the military's investigation remain outstanding. A U.S. defense official said on Wednesday, however that evidence indicates Marines deliberately shot to death unarmed civilians. Murtha, a Pennsylvania Democrat, is being sued by one of the accused Marines for libel....