This seems like a contradiction. Put a prison inmate into a solitary confinement cell and then give him a cellmate. It's called “double-cell solitary confinement”: Two inmates considered so dangerous and violent that they're removed from the general prison population but then put together in one tiny cell, together for 23 to 24 hours a day. NPR's Investigations Unit exposed this little-known practice that is common in federal and state prisons. The series showed how double-cell solitary confinement results in high levels of prison violence and sharply increases the likelihood of inmates killing other inmates.