San Diablo, The Devil's Haven - S.H.J Walton - Bog

They had all heard the rumours about the place of course, but they had dismissed them as jailhouse myth and bullshit, a place where the prison doctor would pronounce you dead, and you would disappear from heart and memory, and enter into Hell on Earth as the warden's guest in San Diablo the devil's haven.
The Devil's Haven is set in the middle of the baking hot desert. Hidden far from public view and scrutiny resides the top-level, top-secret super-max correctional facility, a warehouse of sorts for the very worst of the worst of humanity's dregs and gangsters, those sentenced to death for their heinous crimes, those that no one would miss.
Through twists and intrigue, it soon becomes clear that all is not as it seems at San Diablo, neither is the hyper-sadistic warden, nor his new guest the bizarre and enigmatic high-profile inmate en route to the hell pit, or the mysterious CIA super agents entirely as they seem at the Devil's Haven, San Diablo.