ภาพเหตุการณ์สังหารหมู่ในกรุงวอชิงตัน

Emergency vehicles and law enforcement personnel respond to a shooting at an entrance to the Washington Navy Yard, Sept. 16, 2013.

Police respond to the shooting at the Washington Navy Yard, Sept. 16, 2013.

U.S. Capitol Police personnel keep watch on the East Plaza of the Capitol as the investigation continues to the shooting at the nearby Washington Navy Yard, Sept. 16, 2013, in Washington.

Police who responded to shooting at the Washington Navy Yard, Sept. 16, 2013, leave the facility.

A Metropolitan Police Department officer walks near the Washington Navy Yard after at least one gunman launched an attack inside the Washington Navy Yard, Sept. 16, 2013.

A police helicopter is seen as police walk on the roof of a building as they respond to a shooting at the Washington Navy Yard, in Washington, Sept. 16, 2013.

A police helicopter lifts what appears to be a shooting victim up as it hovers over a rooftop on the Washington Navy Yard, Sept. 16, 2013.

A dog walks around a sculpture "breaching,"created by artist Michael Greve at the Sculpture by the Sea exhibition in Sydney, Australia. Sculptures created by 109 artists from 16 countries, are displayed across the costal area of Sydney.

A helicopter lifts a person off the roof as police respond to the report of a shooting at the Navy Yard in Washington, Sept. 16, 2013.

A police helicopter flies overhead as police walk on the roof of a building as they respond to a shooting at the Washington Navy Yard, Sept. 16, 2013.

Police work the scene near the Washington Navy Yard, Sept. 16, 2013.

A police vehicle is seen as police respond to a shooting at the Washington Navy Yard, Sept. 16, 2013.

Police work the scene after a gunman was reported at the Washington Navy Yard in Washington, Sept. 16, 2013.

Members of the United States Marine Corps maintain a watch on their barracks as police respond to a shooting at the Washington Navy Yard, Sept. 16, 2013.