An investigation of computer records indicated Vos and the juvenile agreed to trade sex for beer and cigarettes, police said.
Prospect Heights school officials and police were looking into whether there were more victims on Monday. A note had been sent home to parents asking them to come forward if they had any information about other possible victims.
Vos, who was being held on a $100,000 bond, was found dead in his home of an apparent suicide.
Vos taught computer education.
