Navy Yard shooting rampage gallery

Investigators say they have not established motive for attack

A U.S. Park Police helicopter removes a man in a basket from the Washington Navy Yard Monday, Sept. 16, 2013.    Earlier in the day, the U.S. Navy said it was searching for an active shooter at the Naval Sea Systems Command headquarters, where about 3,000 people work.  The exact number of people killed and the conditions of those wounded was not immediately known.  (AP Photo/Jacquelyn Martin)
A U.S. Park Police helicopter removes a man in a basket from the Washington Navy Yard Monday, Sept. 16, 2013. Earlier in the day, the U.S. Navy said it was searching for an active shooter at the Naval Sea Systems Command headquarters, where about 3,000 people work. The exact number of people killed and the conditions of those wounded was not immediately known. (AP Photo/Jacquelyn Martin)

A former Navy man opened fire Monday morning inside a building at the heavily secured Washington Navy Yard, spraying bullets at office workers in the cafeteria and the halls, authorities said. Thirteen people were killed, including the gunman.