In a case that still haunts US parents and forever changed the handling of child abductions, Etan Patz vanished on May 25, 1979, after leaving his parents’ home in Manhattan to walk alone for the first time to the school bus stop.

Pedro Hernandez, then 18 years old and working in a convenience store near the bus stop, was convicted at a second trial.

But a federal appeals court ruled in July that Hernandez must be released or re-tried because of errors in the second trial’s conduct.

“The state trial court contradicted clearly established federal law,” the appeals court found, after defense attorneys complained about instructions given to jurors.

Hernandez was arrested in 2012 following a tip to detectives. He had told family members he killed a child in New York, CNN reported at the time.

The first trial ended in 2015 with the jury failing to reach a unanimous verdict.

“The District Attorney has determined that the available, admissible evidence supports prosecuting defendant on the charges of Murder in the Second Degree and Kidnapping in the First Degree in this matter, and the People are prepared to proceed,” said the letter seen by AFP.

In the letter to Judge Ellen Biben, Manhattan prosecutors said they were ready to discuss a retrial during a hearing scheduled for December 1.

Etan’s disappearance shocked Americans and fueled a generation of hyper-vigilant parenting.

His parents only discovered he was missing after he failed to come home from school at the end of the day. His body was never found, and the case was one of the city’s great unsolved crimes for decades.

Photographer Stan Patz’s pictures of his son were the first of a missing child to be featured on milk cartons as part of a nationwide search.