U.S. special operations troops captured Ahmed Abu Khattala in a secret raid in Benghazi on June 15, 2014. He is believed to be the mastermind of the Sept. 11, 2012, attack on the U.S. consulate that killed four Americans, including U.S. ambassador to Libya Christopher Stevens. In July 2014, the U.S. Attorney in the District of Columbia charged Abu Khattala and several others with the felony counts of killing a person in the course of an attack on a federal facility involving use of a firearm, providing material support to terrorists resulting in a death, and possessing a firearm during a crime. He pleaded not guilty to the charges in July.