Tommy Silverstein, who murdered a guard while in jail in 1983, has spent 27 years in solitary confinement, the longest period of such treatment in history, according to his lawyers. He lives in the high-security Supermax prison in Colorado, where the lights are always on and he is fed through a slot in his cell. His lawyers say such treatment violates the Eighth Amendment, which prohibits cruel and unusual punishment. To pass the time, Silverstein crochets and does yoga. "It's almost more humane to kill someone immediately than it is to intentionally bury a man alive," he once wrote a friend. Silverstein first entered prison in 1978 after being convicted of committing robbery.