Attorney General Tim Fox said in a statement Yellowstone County prosecutors will ask Judge G. Todd Baugh to cancel a hearing he has scheduled for Friday to reconsider his own sentence.
Fox said the hearing is meaningless because sentences can only be changed by appealing to the state Supreme Court or by a petition for post-conviction relief.
The victim, who was 14 at the time she was rape, killed herself shortly before her 17th birthday.
Baugh, during sentencing, suggested she shared responsibility for her affair with Stacey Dean Rambold, who was then her teacher at Senior High School in Billings.
Baugh's decision to give Rambold a 15-year sentence with all but 30 days suspended caused outrage, with protesters outside the Billings courthouse demanding his resignation. Baugh later apologized for remarks that the victim was "older than her chronological years" and shared responsibility for the affair with Rambold.
The judge announced the new hearing Tuesday, saying his sentence may have been illegal.