David Duane Cooper, 46, has been a math teacher at North Platte High School in North Platte, Lincoln County, Nebraska, United States since 2006. He is accused of having an inappropriate relationship with a female high school junior, 17.

The teenager also served as a student aid for one of Cooper’s classes. On several occasions, she had been seen entering his classroom after school hours.

In December 2022, the relationship between Cooper and the student became physical, the latter told the North Platte Police Department. He allegedly sexually assaulted her on three different occasions, including once in his classroom.

On February 21, 2023, a North Platte High School administrative staff member reported to the North Platte Police Department that they had received information that the teacher had been acting inappropriately around the student. Cooper allegedly told the student that she would need to delete messages off her phone if their relationship was ever compromised.

On the morning of February 22, 2023, the student was interviewed and several items of evidence were collected. Investigators developed probable cause including evidence of sexual contact between the student and Cooper.

The investigators found 49,204 messages between Cooper and the student in the student’s phone. The messages were sexual in nature.  

In the afternoon, the school resource officer at North Platte High School arrested Cooper. He was placed on administrative leave and booked into the Lincoln County Detention Center in North Platte.

Cooper was charged with sexual abuse by a school employee. If convicted, he could face up to 20 years in prison.