OMAHA, Neb. (AP) — The parents of a student sexually assaulted by an Omaha math teacher have sued the district and some administrators, saying school officials did nothing to stop the teacher.

The federal lawsuit filed last week says the officials didn’t act on reports and suspicions that Brian Robeson was grooming and sexually assaulting a 13-year-old student on and off grounds at Alfonza W. Davis Middle School.

The district and the officials and their lawyers have declined to comment or didn’t return calls.

Robeson pleaded guilty to sexual assault and in October last year was sentenced to 40 years in prison.

The girl’s parents seek undetermined damages for emotional distress, the girl’s ongoing mental health struggles and medical treatment for her physical and emotional injuries.