Washington Navy Yard shooting

On September 16, 2013, Aaron Alexis, a lone man armed with a shotgun, killed twelve people and injured fourteen others in a mass shooting at the headquarters of the Naval Sea Systems Command (NAVSEA) inside the Washington Navy Yard in Southeast Washington, D.C. The attack happened at around 8:20 a.m. in Building 197. Alexis was shot dead by police after he shot at them.
It was the second-deadliest mass murder on a U.S. military base after the Fort Hood shooting in November 2009, and the deadliest mass murder in the Washington metropolitan area since the September 11 attacks in 2001.