Three victims of sexual assault have filed a federal lawsuit against former Major League Baseball player and Detroit Tiger Chad Curtis and Lakewood High School.

Curtis is serving a seven to 15 year prison sentence after being found guilty by a Barry County jury on multiple counts of criminal sexual conduct after a week long trial in August 2013.

He was a substitute teacher volunteering in the school's weight room when the incidents occurred in 2011 and 2012.

The female victims, who were 15 and 16 at the time the assaults occurred, said Curtis took them into the training room under the guise of giving them "rehabilitative massages" and instead inappropriately touched them with sexual intent.

Curtis is accused of battery and intentional infliction of emotional distress; the Lakewood Public Schools and the board of education are charged with violating the girl's constitutional rights and not protecting them from discrimination in education programs or activities based on sex.

The suit alleges school officials at least twice found Curtis alone with a victim in a locked, windowless room and did nothing to deter Curtis from gaining access to female students. The victims are seeking at least $4 million.