An elderly man who spent 24 years in prison for his daughter's death in a fire will remain free after a federal appeals court in Pennsylvania on Wednesday refused to reinstate his murder conviction.

Han Tak Lee, 80, a native of South Korea who earned U.S. citizenship, was exonerated and freed last year after a judge concluded the case against him was based on since-discredited scientific theories about arson. Prosecutors appealed, saying that other evidence pointed to his guilt.

The Philadelphia-based 3rd U.S. Circuit Court of Appeals rejected the appeal, meaning Lee will stay out of prison.

The New York City shop owner had taken his 20-year-old, mentally ill daughter to a religious retreat in Pennsylvania's Pocono Mountains where, prosecutors say, he set fire to their cabin. Lee has long contended the 1989 fire was accidental.

Lee, who returned to Queens after his release from prison, did not answer his phone Wednesday morning. He told The Associated Press in an interview last month that he still loved America and "I expect America to make the right decision."

His attorney was in court and could not be reached immediately for comment on the ruling. Monroe County District Attorney David Christine, who prosecuted Lee in 1990 and whose office filed the appeal, did not immediately return a text and email seeking comment.

Lee's conviction was one of dozens to be called into question around the U.S. amid revolutionary changes in investigators' understanding of how an intentionally set fire can be distinguished from an accidental one.

A state police fire marshal had testified at Lee's trial that the wood in the Lees' cabin was deeply charred and blistered, that the windows had a series of tiny fractures and that he had found at least eight separate points of origin — all evidence of arson, according to the orthodoxies of the day.

The jury convicted Lee of murder and sentenced him to life without parole.

After years of appeals, the 3rd Circuit granted Lee's request for an independent review of the evidence. The review, led by a magistrate judge, concluded the expert testimony used to convict him was based on "little more than superstition."

"The commonwealth concedes that, due to scientific developments since Lee's trial in 1990, the basis for all of this evidence is now invalid," the appeals court said in Wednesday's ruling.

Prosecutors had pointed to what they said was other evidence supporting the conviction, including a pathologist's opinion that Lee's daughter might have been strangled before the fire and Lee's stoic demeanor afterward.

But the appeals judges agreed with the lower court's determination that Lee's passivity at the fire scene likely stemmed from a cultural taboo against showing emotion in public, and said the strangulation theory "was supported by very little forensic evidence."