A former Taliban commander already in U.S. custody has been charged with murder and terrorism-related offenses in the deaths of three U.S. troops and an Afghan interpreter and the downing of a U.S. helicopter in Afghanistan in 2008, federal prosecutors in New York said on Thursday. The U.S. Attorney’s Office in Manhattan said Haji Najibullah was charged in a 13-count indictment that was unsealed in federal court. He was previously charged in the 2008 kidnapping of an American journalist and the new indictment supersedes the earlier one and includes charges related to that incident, prosecutors said. Prosecutors said Najibullah served at the time as a Taliban commander in Afghanistan’s Wardak Province bordering the capital Kabul. He was charged in connection with an attack by Taliban fighters under his command on a U.S. military convoy with automatic weapons, rocket-propelled grenades and other explosives, prosecutors said. The attack killed U.S. Army Sergeants …