The corrupt coaching of a key witness by a police detective, and the failure of prosecutors to turn over information that the witness knew nothing about the crime, has led a federal appeals court to uphold the release of a man convicted of a double murder 20 years ago.

Scott Lewis was convicted in 1995 on the word of a single witness of the 1990 murders of Ricardo Turner, a convicted drug felon and former city alderman in New Haven, Connecticut, and his companion, Lamont Fields.