NBC Wash live stream:
shooter on 4th floor shooting into an atrium
NBC Wash webpage: U.S. military officials say the gunman - armed with an AR-15, a military-style assault weapon - first shot the base security officer.
new info
mult sources: MULTIPLE SHOOTERS
At least TWO SHOOTERS OVERALL
metro buses have been sent in to bring workers out of facility
http://www.nbcwashington.com/news/local/Confirmed-Shooter-at-Navy-Yard-One-Person-Shot-223897891.html
live stream of NBC Wash
At least one of the gunmen has been captured or taken down
—NBC WASH