"A firearm was recovered as a result of an administrative search at the entrance to the rotunda of the Cannon Building at approximately 0920 hours," said US Capitol Police spokeswoman Lieutenant Kimberly Schneider.
Ronald Prestage, 59, was arrested with a 9mm Ruger handgun and charged for carrying a pistol without a license.
Prestage is not a congressional staffer, unlike in Friday's incident when Ryan Shucard, press secretary to Republican Congressman Tom Marino of Pennsylvania, was arrested bringing a handgun and magazine into the same Cannon House Office Building.
In 2007, a senior aide to then senator Jim Webb was arrested for trying to bring a loaded pistol belonging to Webb into a Senate office building.
