Cromartie did not shoot anyone, and it is thickheaded to judge anyone as a murderer except the man who pulled the trigger. If it comes out that the others paid/coerced Grady to kill someone, make your judgment then. But this would not be the first time someone who is not pure evil is a thief but not a murderer, even though he was in a situation where a murder took place. There are dozens of people in this town who will say how Cromartie has helped them in some way, he has been a thief in the past and it is a sad shame he has not completely changed, but any argument to paint Cromartie as a soulless/evil/inhuman/uncaring thug will fall on deaf ears. He made a really big mistake and needs to pay for it, but no one who has ever known him believes for a second he had anything to do with Grady's decision to fire a gun at that poor boy.
You won't hear the same arguments for Grady, fyi.