Prosecutors on Wednesday dismissed charges against a man who spent three decades in prison for a rape conviction even though the victim described her attacker as a man without any facial hair and he had a beard.

George Perrot was convicted of raping 78-year-old Mary Prekop in her Springfield home in 1985 based in part on one strand of hair. But he was freed last year after a judge found an FBI agent’s testimony about microscopic hair evidence was flawed and granted him a new trial.

Prosecutors had appealed the judge’s order for a new trial, but they said in court documents filed Wednesday that “the interests and administration of justice are best served by the termination of prosecution of this matter.”

Perrot said Wednesday that he is now “truly free.”

“Words can’t express how grateful I am for the team of individuals who made this exoneration happen. The people who stuck by me when I was at my lowest and never quit,” Perrot said in a statement through the Schuster Institute for Investigative Journalism at Brandeis University in Waltham, which has been investigating his case since 2011. “This exoneration was hard fought and there were many times over the 30 years that I felt I would die as a convicted man.”

A spokesman for the Hampden district attorney didn’t immediately respond to an email seeking comment on Wednesday.

The judge who released Perrot in February 2016 said he is “reasonable sure” that the man didn’t rape Prekop.

Prekop repeatedly said the man who beat and raped her didn’t have any facial hair. On the night of the attack, Nov. 30, 1985, Perrot had a beard and a mustache.

When Prekop was shown Perrot’s lineup photo during his trial and was asked if he was her attacker, she replied, “How can I say it when this man has a mustache and a beard?”

An attorney for Perrot said the decision means the man, who was 17 when he was arrested, won’t have the cloud hanging over him any longer.

“It was really a huge outcome and a really major win for him,” attorney Christopher Walsh said.

The U.S. Department of Justice flagged Perrot’s case in 2014 as one of hundreds that involved erroneous statements from FBI agents about hair analysis. Microscopic hair analysis has since been found to be far from exact. The FBI now acknowledges that the science is not conclusive and uses it only in conjunction with DNA testing.