DETROIT (AP/WOOD) — More than 300 Michigan prisoners serving no-parole sentences will likely have an opportunity for release after a major decision by the U.S. Supreme Court.

The court says prisoners who have been locked up for years must benefit from a 2012 ruling that outlawed automatic no-parole sentences as cruel punishment for first-degree murder. It applies to people convicted of murder when they were 17 or younger.

Ann Arbor attorney Deborah LaBelle says the reaction Monday has been “tears of joy” in Michigan prisons.

“The brain science has come out and said what every parent knows, what every parent should know, that youth are different than adults; that they’re impulsive,” LaBelle told 24 Hour News 8 over the phone Monday. “They don’t think through things. They don’t have the experience. They don’t think about consequences in the same way.”

At 71, Sheldry Topp is the oldest state inmate serving a no-parole sentence for murder as a teen. He’s been in prison for 53 years.

Roughly 350 prisoners are affected. Around 23 of the affected prisoners are locked up for Kent County crimes.

Among them is Federico “Kiko” Cruz, who was 16 when he was found guilty for the murder of 17-year-old David Crawford, which happened in 1996 near the Sparta airport. Police say Cruz decapitated Crawford and kept it in his home, even making a videotape with it. At the time, investigators told 24 Hour News 8 it was one of the most gruesome crimes they had ever seen.

More recently, in 2006, 17-year-old Giovanni Casper fired several shots at Kentwood Fun Spot skating rink, killing 16-year-old Kenneth Dear. He will also have a shot at parole under the Supreme Court’s ruling.

Prosecutors have been anticipating the ruling issued Monday, but there are still many unanswered questions about what happens next. Kent County Chief Assistant Prosecutor Chris Becker said he doesn’t have an opinion on the ruling — his job is to enforce the law — but he is concerned about putting victims’ families through the details of cases again as inmates convicted as juveniles are resentenced.

“It’s going to be a tough, painful thing to go through and especially dealing with the victims’ families,” Becker said. “You are reopening some wounds that are pretty deep and now we are going to ask them (the families), ‘Hey what do you want to do?’ That’s a tough call for them. “

Prosecutors across the state will have to submit a list of juvenile lifers in their counties. After 180 days, the prosecutors must choose which offenders they want to remain in prison without parole. Those prisoners will have a hearing. It’s unclear whether they will get parole hearings or new sentences. Michigan Attorney General Bill Schuette is reviewing the decision.

The remainder of the prisoners on the list will go before a judge, who will decided the number of years to which they are resentenced.