A Hopland man was arrested over the holiday weekend on suspicion of illegal possession of a firearm and ammunition after a traffic stop in Sonoma County. The Santa Rosa Police Department says officers stopped a vehicle after it was seen driving erratically. Officers searched the vehicle and one of five occupants, a male teen, became combative while being searched. Officers found a .45 caliber handgun and brass knuckles on him, as well as a stolen, loaded .22 revolver in the possession of the driver, Thomas Shaw of Hopland. Shaw was arrested on suspicion of possessing an unregistered firearm, possessing stolen property, having a concealed firearm in a vehicle and being a felon in possession of ammunition. The teen was arrested on possession of an unregistered firearm, carrying a concealed firearm, possession of brass knuckles, illegally possessing ammunition, being a minor in possession of a firearm and for battery on a police officer with injury.