Defense Secretary Chuck Hagel (in blue suit) and Chairman of the Joint Chiefs Gen. Martin Dempsey participate in the laying of a wreath, honoring the victims of an attack at the Navy Yard, at the Navy... more 
Defense Secretary Chuck Hagel (in blue suit) and Chairman of the Joint Chiefs Gen. Martin Dempsey participate in the laying of a wreath, honoring the victims of an attack at the Navy Yard, at the Navy Memorial in Washington, September 17, 2013. Washington authorities questioned on Tuesday how a U.S. military veteran with a history of violence and mental problems could have gotten clearance to enter a Navy base where he killed 12 people before police shot him dead. The suspect, Aaron Alexis, 34, a Navy contractor from Fort Worth, Texas, entered Washington Navy Yard on Monday morning and opened fire, spreading panic at the base just a mile and a half (2.5 km) from the U.S. Capitol and three miles (4.8 km) from the White House. REUTERS/Mike Theiler (UNITED STATES - Tags: MILITARY POLITICS OBITUARY CRIME LAW CIVIL UNREST) less 
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Reuters | Photo By MIKE THEILER / REUTERS
Tue, Sep 17, 2013 10:55 AM EDT