A federal appeals court said Monday that Pedro Hernandez, the man convicted in the decades-old disappearance of 6-year-old Etan Patz, must either be granted a new trial or released from custody, the New York Times first reported.

Hernandez was found guilty of murder in 2017 after confessing to luring Patz into a basement in Manhattan’s SoHo neighborhood in 1979, where he allegedly attacked the boy as he walked alone to his school bus stop.

The Manhattan district attorney’s office first brought charges against Hernandez in 2012. His initial trial in 2015 ended in a hung jury. In a second trial two years later, a jury convicted him after nine days of deliberations.

On appeal, according to The Times, Hernandez’s attorneys argued that the trial court issued improper jury instructions, which they claim unfairly influenced the verdict. The appeals court sided with that argument, opening the door for a retrial or potential release.

This is a breaking news story. Updates to follow.