There was a guy that poisoned his wife and was charged with murder in 1967. He went to a phych hospital that he had worked at years earlier and knew how to escape. 13 years later he had his fingerprints taken in Ireland as he had called police over a break in at his apartment. Needless to say, Interpol determined who this gentleman was and when an extradition treaty between Ireland and USA was established, he was arrested. BUT, there was a glitch in the treaty and 2 years later, the guy was released in Ireland.
Has he ever been found?

Yes I remember that one, that was Joseph Maloney. To my knowledge he was never caught.