TRIPOLI (Reuters) – Gunmen have killed a U.S. citizen working at a world college in the Libyan metropolis of Benghazi, clinical and security sources stated on Thursday. The attackers shot the American man, who used to be an trainer or instructor at the Benghazi faculty, while he exercised within the morning, the sources stated. Nobody claimed accountability for the taking pictures. The U.S. ambassador to Libya was killed in late 2012 when Islamist militants assaulted the U.S. consulate in Benghazi. (Reporting through Ayman al-Warfalli in Benghazi; Feras Bosalum in Tripoli; writing with the aid of Patrick Markey)