CALHOUN COUNTY, IOWA (WHO) — A former teaching assistant with the Manson Northwest Webster School district has been charged with sexually abusing a 14-year-old student. Zach Siefken, 21, was charged on Monday with third degree sexual abuse, lascivious acts with a child and sexual exploitation by a school employee, according to court records.

Police were dispatched to a rural gravel road near Manson in early September on a report of a suspicious vehicle. When an officer approached the car, Siefken and the student were seen inside in the midst of a sex act. A Calhoun County Sheriff’s deputy was called to the scene as well.

According to district officials, Siefken had worked in the district for two years. He resigned his position in late-September. At the time of his resignation, the district was unaware of the investigation into Siefken.

Siefken was employed at the elementary school in Barnham during the current school year. The previous year he worked at the Junior-Senior High School in Manson.