The Marine Corps has completed its investigation into the death of the first Iowan in the war to free Iraq. The death of Sergeant Bradley Korthaus of Davenport has been ruled accidental, and the probe found NO negligence by his commanders. Questions arose after Korthaus and another Marine drown two weeks ago while they tried to cross a swift-moving Iraqi canal, while loaded down with equipment and weapons. They also weren’t on a safety line. Two other Marines survived the crossing. The 28-year-old Korthaus had wanted to be a Marine since he was a boy and enlisted right after graduating from Davenport’s Assumption High School. He was buried yesterday with full military honors at the Rock Island Arsenal’s National Cemetery.