WASHINGTON – U.S. investigators on Sunday returned to a village in Niger where four American soldiers were killed in an ambush in October carried out by Islamist militants, the military said. The news came a day after the Washington Post citing villagers reported that Sgt. La David Johnson, one of the four, was found with his arms tied and a gaping wound to the back of the head. The discovery suggested he was captured and executed. The investigative team, comprising U.S. and Nigerien officials, "returned to the village of Tongo Tongo, Niger, on Nov. 12 in order to gain a clearer understanding of the Oct. 4 ambush, the attack site and the surrounding environment, United States Africa Command (AFRICOM) said in a statement.