BOSTON (AP) – A corrupt former Boston FBI agent imprisoned for protecting fugitive mob boss James “Whitey” Bulger has become an informant after a fellow prisoner allegedly confessed to killing two potential witnesses, The Boston Globe reported.

Prosecutors have yet to act on the information provided by John J. Connolly Jr. and said Monday that Connolly’s word alone was not enough to charge the prisoner with murder. Connolly’s lawyers called for a special investigation into why prosecutors have not brought charges.

Connolly has been in federal prison for 27 months, since he was sentenced on federal charges of racketeering, obstruction of justice and lying to an FBI agent over his handling of Bulger and his gang.

After Connolly arrived at federal prison in Lexington, Ky. in September 2002, he struck up a relationship with Cornelius Anderson, a 38-year-old convicted drug dealer and gang leader. The two worked side-by-side in the same prison job and researched case law together in the prison library.

Anderson also allegedly confided in Connolly, allegedly telling him he had Gail Duncan, a former drug addict and informant, killed in 1996 because she was about to testify in Anderson’s drug conspiracy trial, according to the Globe. She was shot in her car in front of her 9-year-old daughter.

Connolly compared notes with another inmate, Robert L. Rankin, a convicted drug dealer. According to Connolly, Rankin described how Anderson admitted to also killing Deron Cole, 20, a co-defendant of Anderson’s. Cole had pleaded guilty to lesser charges in return for a reduced sentence, and Anderson was afraid that Cole would talk, according to Connolly.

Connolly went to Louisville police in May 2003 with his allegations. Detective Anthony L. Finch, the officer investigating the two murders, interviewed both Connolly and Rankin several times, and said he believes Connolly’s information is credible.

“The bottom line is, the man’s not lying and he’s not wrong,” Finch said. “As far as this case goes, he has been nothing but helpful. He has been nothing but professional. And he has taken a lot of risks to his own life.”

Federal officials, convinced that Anderson had become suspicious of Connolly and Rankin, transferred Rankin to state prison in Illinois, and Connolly to low-security prison in North Carolina.

But nearly 18 months after Connolly brought the information to police, no action has been taken on the case against Anderson.

Connolly’s lawyers on Monday called for a special prosecutor to investigate why the U.S. Attorney’s offices in Louisville and Boston have not made a case against Anderson.

“It’s either incompetence or nefarious behavior,” attorney Edward J. Lonergan said at a news conference.

But Marisa Ford, an assistant U.S. attorney in Louisville and chief of the office’s criminal division, said the call for a special prosecutor was premature.

“This office is fully committed to the prosecution of cases where federal witnesses or informants have been murdered, but we have to have the evidence to go forward with a prosecution. The only evidence that’s been presented to this office is the uncorroborated statements of John Connolly,” Ford said. “Connolly is clearly someone who’s seeking a reduction in his own sentence. … That makes him extremely impeachable as a witness.”

Ford also criticized Connolly’s lawyers for going public.

“They may have potentially compromised a murder investigation as well as placing their own client at risk,” she said.

Samantha Martin, a spokeswoman for U.S. Attorney Michael Sullivan in Boston, said they have no comment.

Connolly admits that he hopes for a reduced sentence, but scoffed at the idea that a possible reduction was the only reason for turning over information about Anderson’s alleged confession.

“I would have done this because we the right thing to do, period,” he told the Globe. “In leniency had been my motivation, I wouldn’t have risked my life without getting a promise in writing.”

Connolly is expected to soon seek a new trial now that Francis “Cadillac Frank” Salemme, one of the mobsters who testified against him, faces new criminal charges of lying to federal agents about a 1993 killing.

Connolly was the FBI’s handler for Bulger, who thrived for decades in Boston’s underworld as an informant. Connolly allowed Bulger to commit crimes in exchange for information that Connolly used to convict other mobsters. Bulger, 75, remains on the FBI’s 10 Most Wanted list, with a $1 million reward for information leading to his capture.