WASHINGTON — The U.S. Capitol was locked down for nearly three hours Saturday after a man shot and killed himself on the west front of the building.

U.S. Capitol Police Chief Kim Dine said the shooting does not appear to have had anything to do with terrorism “or anything related to that.”

The man, whom police did not identify, was walking in a public area on the west front of the Capitol shortly after 1 p.m. when he produced a gun and shot himself, Dine said. He had been carrying a sign with some type of “social justice” message, the chief said.

Immediately after the shooting, police locked down the U.S. Capitol and Capitol Visitors Center as a precaution. Police bomb technicians came in to investigate the man’s backpack and rolling suitcase to make sure they did not contain anything dangerous, Dine said. The buildings were re-opened shortly before 4 p.m.