MASON CITY — A Mason City man has pleaded not guilty to illegal possession of weapons charges. 35-year-old Carlos Cooper is accused of being in the back seat of a vehicle that was stopped by a Cerro Gordo County Sheriff’s deputy in the 900 block of North Adams on the night of December 6th, where the deputy allegedly saw a sawed-off shotgun in the back seat. Cooper was charged with carrying weapons, possession of a firearm as a convicted felon and third-offense possession of marijuana. Cooper’s arraignment hearing was scheduled for today but he filed a written plea of not guilty to the charges in Cerro Gordo County District Court on Monday. District Judge Adam Sauer has scheduled Cooper’s trial to start on March 2nd. Another person in the vehicle, 31-year-old Marcus Jones of St. Paul, fled from the scene during the traffic stop and was arrested a week later in northeastern Mason City. He pleaded not guilty last week to weapons and drug charges and is scheduled to be tried on February 18th.