JTA — A New York federal appeals court ruled Monday to overturn the guilty verdict for the man convicted in the 1979 disappearance of Etan Patz, the Jewish 6-year-old whose kidnapping and presumed murder changed America’s approach to missing-child cases.

Pedro Hernandez, 64, was convicted of Etan’s kidnapping and murder in 2017 and was serving a 25-year sentence until the appeals court ordered Monday that he be released unless he gets a retrial within “a reasonable period.”

Etan went missing in May 1979 on the first day that he was allowed by his mother to walk alone to his school bus stop in New York City. He was one of the first missing children whose picture was placed on milk cartons to seek the public’s help in finding him. Despite extensive searches, he was never found.

In 1998, Etan’s uncle Rabbi Norman Patz told the New York Jewish Week that the family continued to struggle with the pain of not knowing what happened to their son: “It doesn’t go away. And until they discover a body, there’s no closure.”

After Hernandez’s conviction in 2017, Etan’s parents, Julie and Stan, moved from the loft where they still lived on Prince Street to Hawaii, where another son, Ari, lives with his family. (Ari was 2 when his brother disappeared; a sister, Shira, was 8.) A longtime neighbor said at the time that they felt liberated to leave after remaining in the home for decades, in case Etan ever returned.

In its ruling, the appeals court found that the trial judge in Hernandez’s 2017 conviction had given a “clearly wrong” and “manifestly prejudicial” response to a jury note asking whether Hernandez’s initial confession, which was made before he was read his rights, was valid.

The appeals court said the jury should have gotten a more thorough explanation of its options, which could have included disregarding all of Hernandez’s confessions, according to the Associated Press.

Etan’s parents spent decades seeking an arrest for their child’s disappearance, and their advocacy helped to establish a national missing-children hotline. The anniversary of Etan’s disappearance, May 25, also became National Missing Children’s Day.

“They waited and persevered for 35 years for justice for Etan, which today, sadly, may have been lost,” former Manhattan DA Cyrus Vance Jr. told the Associated Press after hearing about Monday’s reversal.