Law enforcement vehicles converge on the scene of a shooting on Constitution Avenue outside the Hart U.S. Senate Office Building as seen from inside the lobby of the building on Capitol Hill in Washington, October 3, 2013. The U.S. Capitol was in lockdown on Thursday after gunshots were fired outside the building, injuring several people including a law enforcement officer, a Senate aide and a Capitol police officer said. REUTERS/David Lawder (UNITED STATES - Tags: CRIME LAW POLITICS)