An Edmonton man who spent eight years in prison for sexually assaulting his nine-year-old stepson has been acquitted after the boy said that his biological father forced him to lie.

The man, who cannot be named under a publication ban, was convicted in 1995 and served his entire prison sentence. He was denied parole because he refused to admit to the offence.

The Alberta Court of Appeal directed a verdict of acquittal in a decision released Monday.

When the child made the claims in the early 90s, his biological parents were involved in a bitter custody battle. Charges were laid after he said his mother's common-law partner sexually assaulted him.

About five years into his stepfather’s sentence, the boy went back to live with his mother.

That’s when he told her that his biological father forced him to make up the story after threatening him with a knife.

While he was still in prison, the stepfather applied to the federal minister of justice for a review of the case.

A special commissioner, Justice Ernest Marshall, was appointed to look at whether the boy’s recantation of his original story could be admitted as fresh evidence.

The commissioner called a number of witnesses, including the boy, who is now an adult. His biological father also testified and denied forcing his son to lie.

In a report sent last year to the Alberta Court of Appeal, the commissioner found the boy’s original testimony to be unreliable and said that his evidence during the trial "consisted of accusations punctuated by retractions," the appeal decision said.

The commissioner came to the conclusion that the boy’s recantations were "worthy of belief."

"Consideration of this testimony gives rise to a reasonable inference that the allegations were false and the recantations were correct," he wrote in his report.

The man's lawyer told CBC News that his client is relieved that the matter is over. The man is now back with his common-law wife and is on good terms with his stepson.