In my story, a gang of crooks gets away with murdering a cop, for lack of admissible evidence. A group of cops who want to avenge their fallen friend, decide to form a vengeful mob, and take out the gang members, but they do so in a way, in which they hope to get away with it, by making it look like a police self defense situation. The gang leader finds out that there is a lynch mob of cops that are after them and want blood. So the gang leader offers to the police to turn himself in, and he will turn over evidence to convict himself, if the cops spare the lives of his fellow gang members. The leader does not want them to pay for what he mostly did, and he wants to spare them from being killed. So this is his way of doing it. However, if he contacts the cops that after him (he knows one of the cop's in the group), and tells them he is willing to turn himself in for the murder of the cop, and provide evidence to prove it, if the cops spare the rest of them, he will need something as evidence he could turn in. I suppose the best thing to do is write it so that the cop's body is never found, but it is highly expected that the gang killed him. So the villain offers to turn over the buried dead body as proof and confess. However, in this situation, what do you think that the vengeful cops that are after the gang's next move would be? Would they not think that deal was good enough, and slaughter the whole gang, or would they think that having the body turned over, with the leader turning himself in, is better than not finding a body at all, with the disadvantage being that they would spare the other gang members lives? What do you think?