Sarosi, the president of Father Gabriel Richard High School’s junior class, was accompanied by twenty-five classmates, teachers, the school’s chaplain, and its principal. They were there because Matilyn, an honor student, had researched and written a “friend of the court” brief arguing that three men serving life sentences for murders they committed as minors deserve a chance for parole. The defense attorneys wanted the students there for symbolic support as they sought to overturn a Court of Appeals ruling against their clients.

Though no one from Gabriel Richard spoke, Matilyn describes the visit as “awesome. It’s incredible to witness the justice system at work.” Others were awed that a teenage girl wrote a compelling legal document. “When I read the brief I was astonished by how good it was,” says Grand Rapids attorney Jon Muth, who filed it with the court. The brief was signed by Sarosi and 452 other Gabriel Richard students.

The Detroit Free Press wrote about Sarosi’s effort, the Associated Press picked it up, and the story went viral. “It’s been an incredible journey,” says Matilyn’s mom, Kimm Sarosi. Letters, emails, and online comments poured in from current and former prisoners and their families, from people concerned about troubled juveniles, and from ordinary citizens impressed or infuriated with her plea on behalf of juvenile lifers. Matilyn says some writers called her “naive” or “an idiot,” complaining that she would give convicted killers a “get-out-of-jail-free card,” an accusation she rejects. What she wants is simply that people imprisoned for actions in their teens be allowed consideration for parole.

Muth says the appeal is being followed closely by defense lawyers throughout Michigan. Last year, the U.S. Supreme Court ruled that it is unconstitutional to sentence juveniles to life without the possibility of parole. But Michigan Attorney General Bill Schuette is arguing that the decision doesn’t apply retroactively to 350-some Michigan prisoners sentenced before the ruling, including the plaintiffs in this case: Dakota Eliason, who was fourteen when he killed his grandfather, and Raymond Carp and Cortez Davis, who were sentenced for involvement in murders committed by others when they were, respectively, fifteen and sixteen. The Court of Appeals sided with Schuette, but the men’s attorneys hope the Michigan Supreme Court will reverse that decision and declare the men eligible for parole.

Matilyn’s interest in juvenile sentencing was kindled through discussions with her lawyer aunt, Mary Ann Sarosi, who helped her with the brief. The final version included psychological and educational research on teenage development, plus Matilyn’s personal and religious perspective. Many teens involved in crime “came from abusive situations,” she says. “It seems very harsh to give them a sentence that doesn’t allow for [the possibility of] redemption.”

The Michigan Supreme Court is not expected to reach a decision until summer–and even that may not be the last word. The dispute over whether its decision should apply retroactively may ultimately end up back in the U.S. Supreme Court.