The Supreme Court, in a 6-3 majority vote, ruled that people serving life sentences in prison without the possibility of parole for crimes they committed as a juvenile should be able to petition for a review for a chance to gain their freedom.

Monday's decision extended a ruling from 2012 that struck down automatic life sentences with no chance of parole for juvenile murderers, reported the Associated Press. Now even those who were convicted long ago must be either given the chance to appeal for a new sentence or considered for parole.

The decision came as the response from a challenge from Henry Montgomery, a Louisiana man who in 1963 at the age of 17 killed a sheriff's deputy in Baton Rouge. He was sentenced to life in prison without parole because the court in his trial was prohibited from considering arguments that his age should matter in their decision.

The opinion of the court was written by Justice Anthony Kennedy and joined by Chief Justice John Roberts and the court's four liberal members, Justices Ruth Bader Ginsburg, Stephen Breyer, Sonia Sotomayor and Elena Kagan, reported NBC News. In doing so, Kennedy said the court's decision in Miller v. Alabama made juvenile offenders eligible for parole.

"This would neither impose an onerous burden on the states nor disturb the finality of state convictions," he said, according to The Hill. "And it would afford someone like Montgomery, who submits that he has evolved from a troubled, misguided youth to a model member of the prison community, the opportunity to demonstrate the truth of Miller's central intuition-that children who commit even heinous crimes are capable of change."

He elaborated, however, saying that the ruling doesn't automatically grant clemency for people serving life sentences and only gives them the chance to be considered for parole or appeal for a new sentence.

"The opportunity for release will be afforded to those who demonstrate the truth of Miller's central intuition - that children who commit even heinous crimes are capable of change," he added. 

SCOTUS' decision reverses the Louisiana Supreme Court's ruling, sending the case back to the lower courts.