Navy Yard Shooter Identified as Aaron Alexis, 34

Information still very sketchy so far

WASHINGTON — At least 12 people, including one gunman, were killed, and the police were looking for other potential suspects, in a shooting Monday morning at a naval office building not far from Capitol Hill and the White House, police officials said.

One police officer was in surgery after being shot in an exchange of fire with a gunman, who was also killed, said Chief Cathy L. Lanier of the Metropolitan Police Department. The shootings took place at the Washington Navy Yard, in the southeast part of the city.

Senior law enforcement officials identified the gunman as Aaron Alexis, 34. A senior law enforcement official said the authorities had identified the gunman through his fingerprints.

Three weapons were found on the gunman: an AR-15 assault rifle, a shotgun and a semiautomatic pistol, the official said.