The family of late crime boss James “Whitey” Bulger is suing the Federal Bureau of Prisons for failing to protect him from being beaten to death by fellow inmates.

The lawsuit, filed Friday in federal court in West Virginia, described the one-time Boston mobster as “perhaps the most infamous and well-known inmate” since Al Capone, according to the Boston Globe.

He was also a well-known “snitch,” yet was transferred to a West Virginia prison known for inmate violence — and where he was killed in a brutal beatdown less than 12 hours after his arrival, the lawsuit said.

“Predictably … inmates believed to be from New England and who are alleged to have Mafia ties or loyalties, killed James Bulger Jr. utilizing methods that included the use of a lock in a sock-type weapon,” the lawsuit claimed.

Bulger was “subjected to a risk of certain death or serious bodily injury by the intentional or deliberately indifferent actions” of prison officials, the lawsuit alleged, according to the Globe.

The actions and practices of prison officials “are shocking to the conscience of civilized persons and intolerable in a society governed by laws and considerations of due process,” the lawsuit alleged.

The lawsuit was brought by William Bulger Jr., Bulger’s nephew and administrator of his estate, and seeks unspecified damages for Bulger’s physical and emotional pain and suffering, as well as for wrongful death.

As well as the Federal Bureau of Prisons, it was filed against 30 unnamed employees of the prison system, including some from US Penitentiary Hazelton, where Bulger was killed, and US Penitentiary Coleman II, where he was incarcerated before his transfer. The family complained that it has never received information about an investigation into Bulger’s death or transfer.

The Bureau of Federal Prisons did not respond to a request for comment.

The one-time leader of the feared Winter Hill Gang, Bulger became one of the nation’s most-wanted fugitives after fleeing Boston in late 1994.

He was finally captured in Santa Monica, California, at the age of 81 after 16 years on the run, and convicted in 2013 of participating in 11 murders and other crimes.

The lawsuit comes a year after the family filed a wrongful death claim with the Justice Department demanding $200 million.

The government has yet to act on that claim, but Bulger’s family expects it will be denied and had to file suit before the statute of limitations expired, according to the latest lawsuit.

Even while held in an Arizona prison housing at-risk inmates, he had been stabbed in the head while sleeping by an inmate who wanted “‘street cred’ for attacking such an infamous criminal figure,” the suit stated.

Instead of increasing his protection, he was moved to Hazelton, which the suit said is dubbed “Misery Mountain” and is “a particularly violent place, where inmate on inmate violence runs rampant and has for many years.”

With Post wires