In my story, the MC who is a cop, is tailing the suspected leader of a gang, on his own time, cause he has a reason to believe that he and the gang of other mystery characters, are behind all the crimes, he is investigating but he has no evidence that is legally solid to do any further investigating. So he is surveying the suspect on his own time. As he is doing this he learns that another cop who he works with in the same department, is corrupt and has been working with the gang leader all along, feeding him information and what not. The gang leader finds out that he is being surveyed by someone who has found out his identity, which is the MC. The leader calls his gang members for help. They try to box in the cop to find out who is onto the leader, and kill him, if need be. The corrupt cop finds out that the gang is up to something and observes. He sees that the MC is in danger and tries to stop it. The MC, thinking that the corrupt cop is there to kill him, since the gang has him trapped, shoots the corrupt cop who has his gun out, thinking the corrupt cop was likely going to kill him. The corrupt cop dies. I want to write it so that the MC pins the death of the corrupt cop on the gang at this point in the story. This results in other cops, who are friends of the corrupt cop, taking revenge on the gang, not knowing that their friend was in collusion with the gang. However, this is where I hit a road block. I mean if let's say the MC gets rid of the physical evidence at on the body, linking him to the corrupt cop's homicide. All he has to do is call in after, that he saw the gang leader kill the corrupt cop. And then the police would be all over it, probably with the MC's word being enough to get search warrants, and maybe even a wire tap order. So if the MC's word is enough to get an investigation going, then the other cops will not feel the need to take revenge, cause the system is working instead. Or maybe the MC does not call it in, cause he takes too much time getting rid of the physical evidence, and it will look too suspicious calling in late, after the time of death? But not sure if a few minutes later would matter. Or maybe the MC wants to get rid of the evidence and just get the heck out of there and not report it, but link the homicide to the gang leader, without having to report it himself for some reason? I keep hitting road blocks on this one, cause I want the revenge to happen for the ending I want, but I keep finding the justice system likely working and the motive of revenge, on the other cops' part therefore, not being needed. So what I mean by my question is, how can the villain get away with a murder, that is pinned on him, so that the revenge can happen? What do you think?