A Cleveland Irish American has been declared innocent, after spending almost a quarter of a century on death row.

In 1988, Michael Keenan was convicted of the stabbing of 19-year-old Tony Klann in a Cleveland Park. Now over two decades later, a judge has dismissed his murder charges.

On Wednesday Cuyahoga County judge John Russo dismissed the aggravated murder count against 62-year-old after he determined that crucial evidence was withheld from his trial attorney.

The judge said the evidence withheld by prosecutors "would have strengthened and been beneficial" to Keenan’s case.

He added that the state’s failure to disclose this evidence "cannot be resolved by a new trial," according  the Associated Press.

The attorney of the accused, John Hildebrand, said his client was "obviously thrilled" with the judge's ruling.

"It's unfortunate that he had to spend that time on death row," Hildebrand said. "A lot of money was spent to keep him there because prosecutors concealed evidence."

Keenan had been convicted twice for the killing of teenager Tony Klann. His first conviction was overturned by the Ohio Supreme Court after they determined prosecutorial misconduct. However he was convicted again in 1994.

Joe D'Ambrosio was also been convicted of murdering the teenager, but a priest who befriended D'Ambrosio uncovered evidence that helped the men prove their innocence.

D'Ambrosio was freed in 2010 by a judge who concluded the evidence could have exonerated him.

Keenan’s attorney said his client was considering suing the state over wrongful imprisonment.