D.C. Police responding Sunday to a report of a gunman at a popular pizza restaurant in Northwest Washington detained a man armed with an assault rifle, according to a police spokeswoman. D.C. police Chief Peter Newsham said a lone suspect in his 20s walked into the front door of Comet Ping Pong with an assault rifle. Newsham said it appeared as if the suspect may have fired one or multiple shots into the ground. The man has not yet been identified and his motives were not clear.