Washington Navy Yard
An employee at a defense contractor used his pass to get into the Washington Navy Yard and went on a deadly shooting rampage Monday, spraying bullets in the hallways and firing from a balcony on workers in an atrium below. Thirteen people were killed, including the gunman. The motive for the attack — the deadliest mass shooting on a military installation in the U.S. since the tragedy at Fort Hood, Texas, in 2009 — was a mystery, investigators said. Mayor Vincent Gray said there was no indication it was a terrorist attack, but he added that the possibility had not been ruled out.