JOLIET (CBS) — A southwest suburban woman has been found guilty of having sex with a Plainfield high school student in 2010.

Will County prosecutors said 36-year-old Shana S. Cox met her victim through her daughter’s boyfriend, and admitted one sexual encounter to police.

A jury deliberated for three hours Wednesday before finding her guilty of one of two counts of aggravated criminal sexual abuse, Will County State’s Attorney’s office spokesman Chuck Pelkie said.

Cox could be sentenced to up to seven years in prison, Pelkie said.

Cox’s victim testified Tuesday he couldn’t remember how many times they had sex, but he said it started in May 2010 when he was a 15-year-old freshman.

He said their last encounter happened two days before they got into a fight that ended with him damaging her car and calling the cops — then telling officers about the relationship.

Under questioning from Cox’s attorney, Neil Adams, the victim also said police didn’t ask him for a DNA sample. Adams stressed to jurors that prosecutors presented no records of text messages between Cox and the boy, and he said the relationship was only revealed after the boy became a suspect in the damage to Cox’s car.

Assistant State’s Attorneys Kathryn Tinich and Tricia McKenna said the text messages weren’t in dispute, nor was the boy’s presence in Cox’s home. They also said it was the boy who called police during his fight with Cox.

Adams said Cox believed the boy was at least 18 when they had sex. He said the boy was 6-feet tall and had facial hair in 2010. Prosecutors said Cox knew the boy didn’t have a driver’s license and picked him up from school.

The victim and a relative of the boy told jurors they initially joked with Cox about the victim’s age, but they eventually told her the truth.

When they did, the victim said, Cox told him, “You’re young.”

(Source: Sun-Times Media Wire © Chicago Sun-Times 2012. All Rights Reserved. This material may not be published, broadcast, rewritten, or redistributed.)