Three men, including a Mafia hitman, were charged in the beating death of notorious Boston crime boss James “Whitey” Bulger in a West Virginia prison, the Justice Department announced Thursday.

Fotios “Freddy” Geas, 55, Paul “Pauly” DeCologero, 48, and Sean McKinnon, 36, were charged with conspiracy to commit first degree murder.

Geas and DeCologero are accused of striking Bulger in the head multiple times and causing his death in October 2018 while they were incarcerated at U.S. Penitentiary Hazleton in Bruceton Mills, West Virginia. In addition to the conspiracy charge, Geas and DeCologero were charged with aiding and abetting first degree murder, along with assault resulting in serious bodily injury.

Geas faces a separate charge for murder by a federal inmate serving a life sentence and McKinnon faces another charge of making false statements to a federal agent.

Known as one of the nation’s most notorious criminals and fugitives, Bulger – nicknamed “Whitey” for his bright platinum hair – was the head of a violent South Boston crime ring known as the Winter Hill Gang from the 1970s into the 1990s. 

He became one of the nation’s most-wanted fugitives, known as a Robin Hood to some and a violent diabolical killer to others, before his eventual capture in 2011. He died at 89 while serving a life sentence for 11 murders and other crimes.

Almost immediately after his death, federal prosecutors acknowledged they were investigating the case as a homicide.

At that time, prison staffers said that one of the suspects who was abruptly moved to segregation pending the outcome of the inquiry was Geas, a known Mafia operative who – like Bulger – was serving a life sentence for a spate of violent crimes, including murder.

MORE ON HIS 2018 DEATH:James ‘Whitey’ Bulger, notorious Boston gangster, found dead in prison; homicide suspected

THE VICTIMS:A look at the 19 murder victims in Whitey Bulger’s trial

Geas and his brother were implicated in the 2003 murder of then-Springfield, Massachusetts, crime boss Adolfo “Big Al” Bruno. Geas’ conviction was won largely on the testimony of informants, a role that Bulger had once embraced for federal authorities to avoid prosecution for his own violent crimes.

Bulger was found in his cell by two officers after it was noted that the elderly inmate had not arrived for breakfast.

Finding Bulger in his bunk wrapped in covers, the officers initially believed he was sleeping. When Bulger did not respond to their presence, the officers removed his bed wrap to reveal a bloodied and severely beaten face and upper body.

“It was a beat-down,” said one of the staffers who viewed the body. “It could have been done with fists or it could have been done with a lock in a sock.”

The staffer referred to a popular makeshift weapon in prison in which ordinary padlocks are placed in socks and swung with force to strike designated targets.

Video surveillance showed at least two inmates going in and later exiting the cell before the body was discovered by the officers, the staffers said.