Santa Paula police said Monday they arrested a person on suspicion of multiple crimes after a traffic stop.The arrest occurred after an officer conducted a traffic stop at 4:54 p.m. Monday on a pickup in the area of Harvard Boulevard and 12th Street for a vehicle code violation, police said.The officer found a gun in the vehicle that was being driven by a person police said was a known gang member who was on probation for narcotics violations and prohibited from owning or possessing firearms.