It's kind of a big 'oops' that has one man wrongly jailed. While most inmates proclaim innocence, one man seems to have the right to do so: Prosecutors won a first-degree assault case which has kept a man in prison since 2006. The only problem--the charge had already been dismissed before the New York guy was ever sent away.
Oswind David -- convicted of "first-degree assault" in a 2006 trial in New York City, New York -- never should have gone to prison legally. Three very important people in the case were unaware of one very important fact: The first-degree assault charge against Oswind David had already been dismissed by another judge, due to prosecutorial error -- before the man was ever put behind bars. But not David, not the judge, and not David's lawyer was aware of that little fact.
Oswind David has been sitting in prison for the roughly five years since his conviction, while serving a 23-year prison term. David was only freed from prison in May when the error came to light -- or was forced to be glaringly obvious.
Considering actions after the fact, it seems arguable the screw-up may not have been entirely missed by a New York prosecutor (or two): The New York City District Attorney tried to resist the release of Oswind David from prison -- trying to argue that only the "first-degree" part of David's case had been dismissed. At lease one judge seems to have had enough: A New York judge finally freed David on bail while prosecutors figure out what they're really doing, supposedly whether or not prosecution will reopen the case.