"We questioned witnesses, and the boy confessed to what was going on," Stringer said. "He said it had been happening since April, mostly at her residence."

Stringer said the boy's mother found the e-mails on her son's computer, printed them out and brought them to the sheriff's office.

"There were graphic exchanges about oral sex," Stringer said. "Things you wouldn't expect a teacher to be sending a child, a student."

Stringer said officers confiscated computers and cell phones at the boy's home and at Schmitz's house in an effort to confirm the e-mails printed by the mother. Investigators were still analyzing the contents of Schmitz's computer Tuesday, Stringer said. The sheriff did not say whether his officers had found e-mails to the student on that computer.