Following a Marshall Project/NPR report detailing violence and abuse at the newest federal penitentiary, three members of Congress asked the Justice Department's inspector general to investigate

Federal prisoners said to be the most dangerous are sent to a special unit at an Illinois penitentiary. NPR and The Marshall Project have uncovered violence, abuse and a string of inmate deaths there.

Federal prisoners said to be the most dangerous are sent to a special unit at a prison in Illinois. NPR and the Marshall Project uncovered violence, abuse and deaths there. Here are five takeaways.

Chuck Coma was one of the thousands of people assaulted in federal prisons each year. His cellmate nearly killed him. But it's now up to his family to take care of him.

The United States Penitentiary at Lewisburg, Pa., is one of the toughest, most violent prisons in America, where inmate-on-inmate assaults are common — and sometimes deadly.

At one of the toughest prisons in America, doubling up inmates in cells designed for solitary confinement can lead to violence, and for some who refuse a cellmate, handcuffs and chains.

Imagine living in a cell smaller than a parking space or a king-size mattress. Now add a roommate. The result for some inmates forced to live together in solitary can be murder.