Crews is an alternate universe version of Vic (The Question) SageThe similarities are rather impressive. Both fought crime, had a rather unfortunate incident, then discovered Zen and resumed crimefighting better than ever. Both are redheads. Both wear blue for crimefighting (The Question's blue suit matched by Crews' bulletproof vest). And both are impressively badass in hand to hand combat.
Crews never got out of prison.He snapped while he was in solitary and the entire show is his hallucination. Think of all the crazy stuff that happens! Wouldn't some of it make more sense if you knew it was dreamed up by an insane man?
Crews is related to Horatio Caine
The first person Charlie killed was a prison guardNot much of a guess. It's pretty implied. We know that he did something to a guard that makes other guards hate him forever afterward. We know that eventhough he was exonerated for murders on the outside, there were rumors of what he did inside. Charlie has said that "everybody breaks" and that the first kill makes you forget who you are and also that at one point even he wasn't sure he wasn't guilty. We also know that the first time Connie came to see him about an appeal, he wouldn't talk to her at all. So, clearly, sometime in the first eight years of his sentence he broke, killed a guard, forgot who he was, started thinking he was capable of killing his friends even though he didn't remember doing it, and decided he belonged in prison. It had to be his first kill or he would have built up a tolerance to those kinds of feelings. He was almost certainly in that "97%" before he went to prison.