Notorious Boston gangster James "Whitey" Bulger may have been beaten to death in a federal prison, according to reports.
The 89-year-old was found dead on Tuesday morning in his cell at the US Penitentiary Hazelton in Bruceton Mills, West Virginia, where he had just been transferred to from Florida.
Bulger was serving two consecutive life sentences after his 2013 conviction for his involvement in 11 murders.
He was the inspiration for Jack Nicholson's crime boss in the 2006 Martin Scorsese movie "The Departed" and was depicted by Johnny Depp in 2015 film "Black Mass".
Authorities have not released a cause of death, although homicide is being investigated, and the FBI is involved in the investigation.
Prison employees told The New York Times that Bulger was beaten to death by at least two fellow inmates.
His body was found at around 8.20am after he failed to come out of his cell for breakfast. He was reportedly wrapped in blankets when prison staff found him.
But there was no love lost for Bulger on the Boston streets he once ruled.
Tommy Donahue, whose father Michael was shot dead by Bulger in 1982 in a hail of bullets intended for someone else, celebrated the mobster's death, telling NBC News: "If I could, I'd put money in the guy's canteen whoever killed him.
"It's going to bring me a lot of pleasure knowing that for eternity he's going to get a pitchfork in the ass from the devil himself."
- Who was James Bulger?
Nicknamed "Whitey" for his bright platinum hair, Bulger grew up in a gritty South Boston housing project and became known as one of the most ruthless gangsters in Boston.
In working-class "Southie," Bulger was known for helping old ladies across the street and giving turkey dinners to his neighbors at Thanksgiving. He had a Robin Hood-like image among some locals, but authorities said he would put a bullet in the brain of anyone who he suspected of double-crossing him.
Bulger's rapsheet started as a juvenile and he spent three years in Alcatraz, the infamous island prison off San Francisco.
He built his power in the 1970s and led a largely Irish mob that ran loan-sharking, gambling and drug rackets in Boston.
But he also was an FBI informant who ratted on the New England mob, his gang's main rival, in an era when bringing down the Mafia was a top priority for the FBI.
He fled Boston in late 1994 after his FBI handler, John Connolly Jr., warned him he was about to be indicted.
With a $2 million reward on his head, Bulger became one of the FBI's "Ten Most Wanted" criminals, with a place just below Osama bin Laden.
When the extent of his crimes and the FBI's role in overlooking them became public in the late 1990s, Bulger became a source of embarrassment for the FBI. During the years he was a fugitive, the FBI battled a public perception that it had not tried very hard to find him.
- How was he caught?
After more than 16 years on the run, Bulger was captured at the age of 81 in Santa Monica, California, where he had been living in an apartment near the beach with his longtime girlfriend, Catherine Greig.
They were caught days after the FBI began a new publicity campaign focusing on Greig. The daytime TV announcements showed photos of Greig and said she was known to frequent beauty salons and have her teeth cleaned once a month.
A woman from Iceland who knew Bulger and Greig in Santa Monica saw a report on CNN about the campaign and called in the tip that led agents to them.
During a search of his Santa Monica apartment, agents found over $800,000 in cash and more than 30 guns, many hidden in holes in the walls.
A property manager at the building said Bulger and Greig, who used the names Charles and Carol Gasko, had lived there for 15 years and always paid the rent-controlled rate of $1,145 a month in cash.
At his trial, prosecutors portrayed Bulger as a purveyor of extreme violence who strangled two women and shot two men dead after chaining them to chairs.
Tom Duffy, a retired state police detective who searched for Bulger, said after his capture: "You could go back in the annals of criminal history and you'd be hard-pressed to find anyone as diabolical as Bulger."
Bulger was convicted of the murders, as well as extortion and money-laundering, in 2013 and sentenced to two consecutive life sentences plus five years.
Greig is still serving her sentence at a federal prison in Minnesota.
- What has the reaction been to his death?
A lawyer who represented Bulger blamed his death on decisions made by the Federal Bureau of Prisons.
Attorney JW Carney Jr said in a statement that Bulger "was sentenced to life in prison, but as a result of decisions by the Federal Bureau of Prisons, that sentence has been changed to the death penalty".
Brian Kelly, one of the former prosecutors who tried Bulger, said: "Hopefully the seven years he spent in prison as well as his recent death brings some closure to the families of his many victims."
The families of some of his victims celebrate the news of his death.
Steven Davis' sister Debra was dating Bulger's partner Steve "The Rifleman" Flemmi, who testified that he lured her to a house where Bulger strangled her. He described it as "a happy day", telling CNN: "He had it coming to him and it's just sad that it took so long.
"He didn't have the right to live as long as he did."