Four 17-year-old Moorpark boys have been arrested after a sporting goods store owner implicated them in a scheme to sell more than $30,000 worth of stolen baseball cards, police said. Two of them approached Greg Sullivan and offered to sell the owner of Sully's Sports Center a 1954 Ted Williams card for less than half its $250 value, said Detective David Lea of the Ventura County Sheriff's Department. Sullivan, who lost more than $8,000 worth of rare cards in a burglary Sept. 14, was suspicious and refused to buy the card. After one of the youths rattled off a list of vintage 1950s cards that he said belonged to his grandfather, Sullivan said he realized these could be cards stolen from a collector in a Nov. 26 burglary. Sullivan helped identify the youths from Moorpark High School yearbook pictures, and deputies arrested the four youths, Lea said. Two face felony burglary charges and the other two face charges of possession of stolen property, the detective said.