Last Updated Apr 11, 2015 9:12 PM EDT
WASHINGTON -- A precautionary lockdown of the U.S. Capitol was lifted after about two hours Saturday following a suicide by a man carrying a protest sign.
The man died after shooting himself on the west front of the Capitol building just after 1 p.m., Capitol Police spokeswoman Kimberly Schneider said. No one else was hurt.
Officials from the FBI's Washington field office told CBS News that the shooting was not believed to be related to terrorism. The FBI's joint terrorism task force was on the scene providing bomb squad support.
Capitol Police Chief Kim Dine said the man had a backpack and a rolling suitcase, triggering an hours-long lockdown, and a sign that said something about "social justice."
Robert Bishop of Annapolis, Maryland, said he was biking near the steps of the Capitol when the suicide happened.
Bishop didn't witness the suicide but said there were about 60 people in the area, and that some of them did, including a girl and her mother who immediately began crying afterward.
Bishop said another witness told him and a police officer that the man who committed suicide held up a protest sign about taxation just before pulling the trigger.
No one was allowed to leave or enter the Capitol or the visitors' center during the lockdown on a busy day for tourists, and some streets around the area were closed.
After being allowed to leave the Capitol, Bishop said he saw authorities taking clothes out of the suitcase the man had.
During the lockdown, about a dozen police cars, black SUVs and an ambulance congregated at the bottom of the west steps of the Capitol, which overlooks the bustling National Mall.
Police appeared to take measurements as bomb squad members searched the area. Nearer the mall, visitors gathered around trying to figure out what was going on.
The lockdown came during Washington's annual Cherry Blossom Festival, which attracts thousands of tourists during Washington's busy season.
Congress has been on spring recess for two weeks and lawmakers are set to return to work Monday.