An MDC, unlike a Federal Penitentiary, is designed to hold prisoners who have not yet been arraigned, have been denied bail, or are awaiting trial.
An MDC is considered to be an administrative facility, as defined by the Bureau of Prisons:
Administrative facilities are institutions with special missions, such as the detention of pretrial offenders; the treatment of inmates with serious or chronic medical problems; or the containment of extremely dangerous, violent, or escape-prone inmates.
On arrival at the Metropolitan Detention Center, Brooklyn, New York, the detainees were slammed face first into a wall against a shirt with an American flag; the bloodstain left behind was described by one officer as the print of bloody noses and a mouth.
Once inside they were threatened with detention for the rest of their lives, verbally abused, exposed to cold, deprived of sleep, and had their hands, cuffed arms, and fingers severely twisted.