Better still... tell him that he will be shot by a police sniper while in prison. But not when or where. Let every trip into the exercise yard or other open area be an occassion of fear and terror, as he tries to scan around for a glint of sunlight off of a rifle scope...
And then have the sniper intentionally miss the first few times...
And the first 10 times he's shot at, the sniper deliberately misses him by inches while the guy dives for cover. One of those times, the shots come right through the window of his cell. Then one day, the sniper gets him -- in the right hip. He survives. A few months later, he gets him in the left knee and again he survives. Things go on like this for years. One day, a hand. Couple months later, an ear -- until the man literally turns yellow with the constant fear and anxiety. Prison bookies start giving even odds on whether he dies by sniper or dies by hanging himself.