A staffer with the House Chief Administrative Office was arrested Thursday morning after bringing a handgun into the Longworth House Office Building.

Jeffrey Allsbrooks, 57, was “tracked down four minutes later and arrested” after Capitol Police officers saw the handgun image in a bag belonging to Allsbrooks on the x-ray screen, the department said in a statement. Officers spotted the gun around 7:40 a.m.

Allsbrooks told officers he “forgot the gun was in the bag,” the Capitol Police statement said. He is being charged with carrying a pistol without a license.

The case is under investigation and the department is examining “what happened before, during and after those four minutes.”

The incident resulted in alerts for the campus. A Capitol Police alert at 7:48 am said there was a door closure at the South Capitol Street door of the Longworth building due to “police activity.” Minutes later the alert said there was a “security threat inside” Longworth and instructed staff to move inside the closest office and lock the doors and windows. The threat was later cleared.

The House Chief Administrative Officer provides support services and business solutions for the members and staff. A spokesperson for the office did not respond to a request for comment.

The arrest comes the same day many top U.S. officials, including President Joe Biden, will honor the late Senate Majority Leader Bob Dole, R-Kan., as he lies in state in the Capitol Rotunda.