Exonerated on January 31, 2001
Louis Greco was convicted of the 1965 murder of Edward Deegan, who was shot to death in an alley. The FBI used wire taps in order to eavesdrop on mob members as they asked permission to kill Deegan, who had insulted them. The FBI did nothing with this information, but instead let the hit take place. Deegan was found in Chelsea, Massachusetts after being shot six times with at least three different guns.
Greco was exonerated almost forty years later, after an FBI taskforce discovered evidence that he was convicted based on perjured testimony. Joseph Barboza, a mob informant, testified against Greco and his co-defendants. It was later discovered that the FBI hid information that could exonerate the men because they were trying to protect Barboza, their informant. Sadly, Greco died in prison in 1995 from colon and heart cancer. He was not formally exonerated until 2004, and spent more than 28 years in prison before his death.