A federal appeals court overturned a guilty verdict in the case of a man convicted in the 1979 killing of 6-year-old Etan Patz in New York City, which could be considered one of the most notorious missing child cases in the country.

Pedro Hernandez was convicted in February 2017 of killing Etan. The conviction came just five years after Hernandez confessed to police that he lured the boy into the basement of the convenience store he worked at, using soda.

Prosecutors said Hernandez choked Etan, stuffed his body into a plastic garbage bag hidden inside a box, and took it out with the trash.

Hernandez was sentenced to 25 years to life behind bars in April 2017.

A newspaper with a photograph of Etan Patz is seen on May 28, 2012, at a makeshift memorial in the SoHo neighborhood of New York, where Patz lived before his disappearance on May 25, 1979. (Mark Lennihan/AP Photo)

However, the defense claimed he was mentally unstable, and incapable of keeping the truth separate from fiction. “Pedro Hernandez is an odd, limited and vulnerable man,” defense attorney Harvey Fishbein said during closing arguments.

Defense lawyers also pointed to a different man who was long the prime suspect — a convicted Pennsylvania child molester who made incriminating remarks about Etan’s case in the 1990s and who had dated a woman acquainted with the Patz family. He was never charged and denied killing the boy.

The sentencing was the culmination of a long quest to hold someone criminally accountable in a case that affected police practices, parenting and the nation’s consciousness of missing children.

Since the boy’s disappearance, law enforcement and volunteers have beefed up their capabilities in finding missing or lost children, establishing a nationwide network of search teams. The National Center for Missing and Exploited Children was incorporated in 1984 and soon launched a 24-hour hotline for tips.

National Missing Children’s Day is held every May 25 — the day in 1979 that Patz vanished.

Fox News’ Mike Arroyo and Lissa Kaplan, as well as The Associated Press, contributed to this report.