Story highlights Stacey Rambold admitted to raping 14-year-old Cherice Moralez

She committed suicide before he went to trial

Rambold was sentenced to 31 days in prison -- plus 14 years, 11 months probation

Judge's ruling is being appealed by prosecutors, who say two years is the minimum sentence

His lenient sentence and the judge's comments about his victim sparked national outrage and protests.

On Thursday, Stacey Rambold, an admitted rapist, will be released from incarceration after just 31 days.

The former high school teacher is set to walk out of the Montana State Prison in Deer Lodge at 9 a.m. (11 a.m. ET).

He won't be a free man exactly; he's on probation for the next 14 years, 11 months.

The victim's mother is hopeful that will change.

"( Judge G. Todd Baugh ) made a mistake and I'm disappointed, (31) days, that's outrageous, but the Montana Supreme Court stepped in. Hopefully they'll make it right," said Auliea Hanlon, whose daughter, Cherice Moralez , committed suicide before Rambold went to trial.

Prosecutors have appealed the sentence -- saying it is illegal -- to the high court.

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Activists file formal judicial complaint

On Tuesday, the Montana and Pennsylvania chapters of the National Organization for Women and an activist group called Ultraviolet filed a complaint with a judicial review board, CNN affiliate KULR reported . More than 140,000 people signed accompanying petitions, the groups said.

"If we can't get him removed from this, there is something wrong with the system, and I know people in the state will work to not get (Baugh) re-elected (next year)," said Marian Bradley, president of Montana NOW.

The case drew widespread attention when Baugh imposed a one-month sentence on Rambold and made controversial comments about the victim, saying she "seemed older than her chronological age" and she was "as much in control of the situation."

Rambold admitted raping the girl in 2008 while she was 14 and he was her teacher at her high school. Moralez took her life shortly before her 17th birthday.

The judge later apologized for his comments, and earlier this month tried to revisit his sentence. But the state Supreme Court barred him from a new ruling, saying he didn't have the legal standing to change a sentence.

Baugh said he didn't realize at first that the minimum sentence should have been two years.

Baugh's secretary said Wednesday the judge had no comment on Rambold's release.

Hanlon told CNN's Anderson Cooper that she wants to avoid Rambold.

"I never saw him until we were in a courtroom all those years," she said. "I hope I never see him (again)."

Defense attorney Jay Lansing had no comment on the case, but has said his client contends the sentence imposed is lawful and appropriate.

The legal process

With Cherice's death, the prosecution entered into what is known as a "deferred prosecution agreement" with Rambold.

This meant that all charges against Rambold -- who admitted to one of the rape charges -- would be dismissed if he completed a sex-offender treatment program and met other requirements. One of them was to have no contact with children.

But the ex-teacher fell short of the agreement and prosecutors asked Baugh last month to sentence him to 20 years.

Baugh ruled Rambold's infractions weren't serious enough.

"He made some violations of his treatment program," the judge said. "They were more technical and not the kind you would send someone to prison for."

Hanlon said the pain of her daughter's death hasn't faded.

"I think we just get used to it, so we don't cry every day," she said, but the tears still came.