Six advocacy groups said in a friend of the court brief filed Friday that justices should order a re-sentencing to restore trust in the judiciary.
District Judge G. Todd Baugh said in August that the 14-year-old victim appeared "older than her chronological age." He sentenced former Billings teacher Stacey Rambold to 15 years prison with all but one month suspended for violating the terms of his deferred prosecution agreement.
The judge later apologized and made a failed attempt to re-sentence Rambold.
An appeal by prosecutors is pending. Rambold has not responded to the state's argument that he should serve a minimum four years in prison.
The victim killed herself before the case went to trial.