Three men charged in the 2018 prison killing of notorious Boston gangster James “Whitey” Bulger have reached plea deals with prosecutors, according to court papers filed Monday.

The plea deals for Fotios “Freddy” Geas, Paul J. DeCologero and Sean McKinnon were disclosed nearly six years after the 89-year-old gangster was beaten to death in his cell at a troubled West Virginia prison.

Fotios “Freddy” Geas is one of three men charged in the prison killing of notorious Boston gangster James “Whitey” Bulger. Don Treeger/The Republican via AP, file

Geas, a onetime Mafia hitman, and DeCologero, a Massachusetts gangster, were accused of repeatedly hitting Bulger in the head while McKinnon served as a lookout.

DeCologero told an inmate witness that Bulger was a “snitch” and that as soon as he came into their unit, they planned to kill him. DeCologero also told an inmate that he and Geas used a belt with a lock attached to it to bludgeon Bulger to death, prosecutors said.

Geas and DeCologero were identified as suspects shortly after Bulger’s death, but they remained uncharged for years as the investigation dragged on.

Prosecutors in West Virginia federal court asked the court to schedule hearings for the men to change their not-guilty pleas and to be sentenced, though they didn’t provide further details about the plea agreements, which have not been filed in court.

Belinda Haynie, an attorney for Geas, declined to comment Monday. Attorneys for the other two defendants didn’t immediately respond to requests for comment from The Associated Press.

The Justice Department said last year that it would not seek the death sentence for Geas and DeCologero, who were charged with murder. All three men were charged with conspiracy to commit first-degree murder, which carries up to a life sentence. McKinnon was also charged with making false statements to a federal agent.

James “Whitey” Bulger in his booking photo in 2011. U.S. Marshals Service via AP, file

Bulger, who ran the largely Irish mob in Boston in the 1970s and ’80s, served as an FBI informant who ratted on the main rival to his gang. He became one of the nation’s most-wanted fugitives after fleeing Boston in 1994 thanks to a tip from his FBI handler that he was about to be indicted. He was captured at the age of 81 after more than 16 years on the run.

In 2013, he was convicted in a string of 11 killings and dozens of other gangland crimes, many of them committed while he was said to be an FBI informant.

Bulger was killed just hours after he was transferred from a Florida lockup to USP Hazelton in West Virginia and placed in the general population. Bulger’s transfer to Hazelton, where workers had already been sounding the alarm about violence and understaffing, and his placement in the general population instead of more protective housing was widely criticized by experts after his killing.

A Justice Department inspector general investigation found in 2022 that his killing was the result of multiple layers of management failures, widespread incompetence and flawed policies at the Bureau of Prisons. The inspector general found no evidence of “malicious intent” by any bureau employees, but said a series of bureaucratic blunders left Bulger at the mercy of rival gangsters behind bars.

DeCologero, who was in an organized crime gang led by his uncle in Massachusetts, was convicted of buying heroin that was used to try to kill a teenage girl his uncle wanted dead because he feared she would betray the crew to police. The heroin didn’t kill her, so another man broke her neck, dismembered her and buried her remains in the woods, court records say.

Geas was a close associate of the Mafia and acted as an enforcer, but was not an official “made” member because he is Greek, not Italian. He and his brother were sentenced to life in prison in 2011 for their roles in several violent crimes, including the 2003 killing of Adolfo “Big Al” Bruno, a Genovese crime family boss in Springfield, Massachusetts. Another mobster ordered Bruno’s killing because he was upset he had talked to the FBI, prosecutors said.

McKinnon had been on federal supervised release after serving prison time for stealing guns from a firearms dealer when he was arrested on charges in Bulger’s killing.

Raby reported from Charleston, West Virginia.