MIAMI, Florida (CNN) -- A judge sentenced a rogue FBI agent to 40 years in prison on Thursday for the 1982 mob-related killing of a witness who was about to testify against Boston mob members, court officials said. Former FBI agent John Connolly "crossed over to the dark side," a judge said. Disgraced ex-FBI agent John Connolly Jr. "crossed over to the dark side," said Miami-Dade Circuit Court Judge Stanford Blake. The sentence will run consecutively to a 10-year racketeering sentence. Connolly, 68, was convicted in November of second-degree murder in the death of businessman John Callahan, an executive with World Jai-Alai. Callahan's bullet-riddled body was found in the trunk of a Cadillac parked at Miami International Airport.
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NEW: Ex-FBI agent "crossed over to the dark side," judge says
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Sentence will run consecutively to previous 10-year racketeering sentence
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John Connolly Jr. has denied role in 1982 mob hit
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He was convicted of second-degree murder in slaying of gambling exec
@placeholder's fall from celebrated mob-buster to paid gangland flunky captivated a South Florida courtroom for weeks.