Marion Federal Penitentiary was the site of Project Flatline, the Orpheus Group and NSA's experiment involving projection by means of drugs and cryonics. The facility holds maximum security and death row prisoners. It was from this latter category that test subjects for Project Flatline were selected.
The Project was successful, but the convicts involved soon realized they could escape into the afterlife and freedom, and all it would cost them was their bodies. They fled, and Orpheus and the NSA were left with twelve corpses and twelve free ghosts who were supposed to be put to death for violent crimes. To cover up the problem, NSA agents overseeing the project ordered the Orpheus scientists under their control to gather materials and set the building on fire; they did just that, and the death row wing of Marion was utterly destroyed. Twelve convicts officially did not make it out, as the bodies of the Flatliners were consumed in the fire. The records of Project Flatline were sealed; it is assumed that the rest of Marion went back to being a regular prison after these events.