A man has been released from a US prison after serving more than three decades for crimes he did not commit.

Keith Allen Harward, 60, walked free from Nottoway Correctional Center after the Virginia Supreme Court ruled that DNA evidence proved he did not kill Jesse Perron and rape Mr Perron's wife in 1982.

Mr Harward, a former sailor on the USS Carl Vinson, was convicted largely on the evidence of two experts who said his teeth matched bite marks on the woman's leg.

Virginia's attorney general said the DNA evidence actually implicated Jerry L Crotty, a former shipmate of Mr Harward's, who died in an Ohio prison in 2006.

"The detectives, prosecutors, judges, forensic scientists went out of their way to convict me," Mr Harward said. "They weren't looking for the truth, they were looking for a conviction."

Mr Harward broke down when he described the effect his wrongful conviction had on his parents.

"That's the worst part about this," he said. "It killed them. It devastated them. I couldn't go to their funeral."