A math teacher at a Southern California middle school charged with molesting four girls is likely to have other victims, investigators said Friday. Richard Rack, 50, was arrested Thursday for the second time in the investigation, the Los Angeles Times reported. He was being held in lieu of $1 million bail. Jim Amormino, a spokesman for the Orange County Sheriff\'s Department, said Rack was in touch with one of his victims while he was out on bail after being arrested this month. \"His behavior leads us to believe there may be other victims out there,\" Amormino said. Rack is a teacher at Shorecliffs Middle School in San Clemente. A teenage girl reported in November that Rack had asked her to wear low-cut dresses to school and had hugged and kissed her. Three other alleged victims later came forward, including one who said Rack had a sexual relationship with her for two years. The Capistrano Unified School District suspended Rack Dec. 1.