special investigator for the Bureau of Prisons who worked at Fort Dix in the late 1990s.

Maraviglia said the New Jersey prison is known as one of the cushiest in the federal prison system. It has segmented housing areas that are more difficult to monitor than at other facilities, making it easier for inmates to hide and use contraband items like cellphones.

 A high-profile guy like that, with all that money, I'm surprised they put him at a place like Fort Dix,  Maraviglia said.

Inmates placed in the SHU are locked in a cell with one other person for at least 23 hours a day, according to two men who spent time at Fort Dix. Inmates are allowed a book or two and a wind-up radio, the sources said, and they must wear an orange jumpsuit instead of the regular khaki uniform or grey sweatpants and shirts.

Meals are delivered in trays but commissary access is restricted, and they are permitted to shower only a few days a week. The sources said they must otherwise wash up in a sink.

 It's nasty down there,  one of the sources said.

It isn't Combs' first time in solitary confinement at Fort Dix. Last summer, he was placed in the special housing unit after he got into a fight with another inmate.

He was later kicked out of a drug treatment program at the prison but continued paying inmates to do a range of services for him, NBC News reported Tuesday.

The story prompted responses from people as varied as Combs' longtime nemesis 50 Cent and the prominent attorney Gloria Allred, who represents a woman suing him for allegedly raping her more than 20 years ago. (Combs has denied the allegations, and the case is ongoing.)

 These serious allegations against Mr. Combs cry out for an immediate federal investigation and appropriate federal action including a prosecution if the allegations of having and using a cell phone while incarcerated can be proven beyond a reasonable doubt,  Allred said in a statement.

Combs' trial last year centered on drug-fueled orgies he organized called  freak offs.  They involved male sex workers and his former girlfriends - including the singer Cassie - who filed a lawsuit against Combs alleging years of physical and sexual abuse. (The case was settled, with Combs denying any wrongdoing.)

The trial ended in a split verdict, with a New York jury finding him not guilty on the more serious charges of sex trafficking and racketeering charges that could have put him in prison for life.