CHICAGO (CBS) — A former suburban high school teacher accused of having sex with a student had entered a not guilty plea.

Ashley Blumenshine, 27, was a teacher at Plainfield North High School. She was arrested behind a Kohl’s department store at 11860 S. Route 59 in Plainfield earlier this month, when police caught her in a car with a 16-year-old boy and determined that they’d had sex shortly before the officers arrived.

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She is charged with sexual abuse and is free on bond. She appeared in Will County court with her attorney on Wednesday.

Blumenshine has resigned. The school district is also taking steps to revoke her teaching certificate.

She had taught dance and physical education at the school for four years.

When Blumenshine was arrested, police noticed two vehicles in the parking lot were sitting much farther out from the store than other vehicles in the lot.

They found one vehicle was empty, and the other contained Blumenshine and the boy, who was partially unclothed.