WASHINGTON (AP) - The D.C. mayor says 13 people have died in the shooting rampage, including the gunman.
Mayor Vincent Gray said at a news conference Monday afternoon that the shooter was among the dead. Officials say the gunman has been identified as 34-year-old Aaron Alexis.
Earlier in the day, authorities had been looking for two other people who may have been involved in the shooting. One of those people has been identified and ruled out as a suspect.
However, Gray says investigators are still searching for a third individual wearing an olive-green, military-style uniform to determine if he was involved.
Gray says a motive has not yet been determined.
In all, more than a dozen people were shot, at least half of them fatally. It was not immediately clear whether that number included the dead gunman.
The attack unfolded just a short distance from the White House and the U.S. Capitol at a former shipyard that is one of the Navy's oldest shore facilities.
The building that was targeted was the military's headquarters for Naval Sea Systems Command, which buys, builds and maintains ships, submarines and combat systems. About 3,000 people work at the headquarters, many of them civilians.
Naval Sea Systems Command is the largest of the Navy's five system commands and accounts for a quarter of the Navy's entire budget. Only security personnel were allowed to be armed on the campus.
The Navy Yard has three gates, according to its website. One is open around the clock and must be used by visitors. A second gate is only for military and civilian Defense Department employees. The other gate is for bus traffic.
The Navy Yard is part of a fast-growing neighborhood on the banks of the Anacostia River in southeast Washington, just blocks from the Nationals Park baseball stadium.
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