A retired Los Angeles County sheriff's sergeant was arrested on suspicion of selling cocaine and marijuana. Sgt. Ron Bailey said Richard Hopkinson, 43, whose last assignment was in the Men's Central Jail, was arrested at his La Mirada home after a three-month investigation. He said narcotics investigators found "a small amount" of drugs--four small plastic bags of marijuana and three bindles of cocaine--in the house. Hopkinson was booked at the Central Jail and held in lieu of $5,000 bail.