CLARKSBURG, W.Va. (AP) — A former Mafia hitman was sentenced Friday to 25 years in prison for the 2018 fatal prison beating of notorious Boston mobster James “Whitey” Bulger.

Federal inmate Fotios “Freddy” Geas was sentenced in a federal court in northern West Virginia after pleading guilty to manslaughter and assault resulting in serious bodily injury.

Prosecutors said Geas repeatedly struck the 89-year-old Bulger in the head with a lock attached to a belt, hours after he arrived at the troubled U.S. prison in Hazelton from another Florida prison in October 2018. Defense attorneys disputed that characterization, arguing that Geas struck Bulger with his fist.

Geas, 57, was already serving a life sentence for previous violent crimes. The Justice Department said last year it would not seek the death penalty for Bulger’s murder.

Bulger, who led the largely Irish gang in Boston in the 1970s and 1980s, was also an FBI informant who betrayed his gang’s chief rival, the bureau said. Bulger has vehemently denied ever being a government informant.

Bulger became one of the country’s most wanted fugitives after fleeing Boston in 1994 after a tip from his FBI contact that he was facing charges. He was captured at age 81 after more than 16 years on the run, and convicted in 2013 of 11 murders and dozens of other gangland crimes.

Another Hazelton inmate, Massachusetts gangster Paul J. DeCologero, was sentenced in August to more than four years in prison for assault in connection with Bulger’s murder. Prosecutors say he served as a lookout for Geas. A third inmate, Sean McKinnon, pleaded guilty in June to lying to FBI agents. McKinnon received no additional prison time and was sent back to Florida to complete his parole. He had been serving time for stealing guns from a gun dealer.

According to court records, inmates learned in advance that Bulger would arrive at the West Virginia facility. DeCologero and Geas spent about seven minutes in Bulger’s cell during the attack.

An inmate testified before a grand jury that DeCologero told him Bulger was a “snitch” and that they planned to kill him if he came into their unit.

Geas was a close associate of the Mafia and served as its 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 murder of Adolfo “Big Al” Bruno, a Genovese crime family boss in Springfield, Massachusetts. Another mobster ordered Bruno’s killing because he was angry that Bruno had talked to the FBI, prosecutors said.

On May 13, the plea agreements for Geas, DeCologero and McKinnon were announced. Geas and DeCologero were identified as suspects shortly after Bulger’s death, but they went uncharged for years as the investigation dragged on.

After the killing, experts criticized Bulger’s transfer to Hazelton, where employees have previously raised alarms about violence and understaffing, and his placement in general population rather than in protective housing.

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

That year, a federal judge dismissed a lawsuit filed by Bulger’s family against the agency and 30 unnamed prison system employees.

In July, the U.S. Senate passed legislation to overhaul oversight and increase transparency within the agency after The Associated Press reported systemic corruption in the federal prison system, leading to increased congressional oversight.