A three-judge panel of the U.S. Court of Appeals for the Second Circuit on Monday overturned the 2017 state-court conviction of Pedro Hernandez for the 1979 kidnapping and murder of six-year-old Etan Patz in New York City. The judges ruled that the trial judge gave improper instructions when responding to a jury note, violating clearly established federal law and rendering the error not harmless. Hernandez, now 64, has been serving a 25-years-to-life sentence. He was first tried in 2015, but that proceeding ended with a hung jury. A second jury convicted him after hearing a 2012 confession he gave following roughly seven hours of police interrogation, a statement his lawyers argued was unreliable because of mental illness. The appellate ruling directs the state either to retry Hernandez or release him. The Manhattan District Attorney’s Office said it is reviewing the decision, which could send the decades-old, high-profile case—one that helped spark the national missing-children movement—back to court for a third time.