A fellow inmate of James "Whitey" Bulger gives RadarOnline.com a glimpse into the hellish conditions the crime boss, who has been charged with 19 counts of murder, is held under.

"He's being kept in the hole," Adrian Alves, who is currently incarcerated in a separate unit at Plymouth County House of Corrections, tells RadarOnline.com in an exclusive interview.

"The cell is like 8 x 12, it's very limited, there's no fresh air - it's like a dog cage. He has a guard outside his cell 24 hours a day and when he is moved he wears a three point restraint, which is a waist chain with shackles down to the ankles and up to the wrists and he is flanked by, like, 20 guards. His cell is shaken down twice a day to check there's nothing in there.

He was number two on the FBI’s Most Wanted List – right behind Osama bin Laden. (When bin Laden died, he became number 1).

After spending 16 years on the run, Boston-based mafia kingpin James "Whitey" Bulger will face a federal judge in a Los Angeles courtroom Thursday to face charges of murder, conspiracy to commit murder, narcotics distribution, extortion and money laundering, among others.

Bulger, who inspired aspects of Jack Nicholson's character in the Oscar-winning 2006 film The Departed, has appeared on the FBI's Ten Most Wanted list -- with a $2 million reward for key info -- in connection with 19 murders he's tied to.

The FBI said Bulger, who was allegedly the head of Boston's Winter Hill Gang, played a “role in numerous murders committed from the early 1970s through the mid-1980s in connection with his leadership of an organized crime group that allegedly controlled extortion, drug deals, and other illegal activities.”

UPDATE: Bulger is now in flight to Boston.

One of the world’s most dangerous men -- James “Whitey” Bulger -- and his companion Catherine Greig are expected to be extradited back to Boston Friday to face charges there after 16-years on the lam.

Bulger -- who shot up to number one on the FBI’s Most Wanted List after the death of Osama bin Laden --  was arrested Wednesday in Santa Monica, California after eluding authorities since 1994.

Once back in Boston, he will face charges in connection with 19 murders in Massachusetts, as well as slayings in Oklahoma and Florida.

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