Oh you are not the bad guy, we will take your word on it?
Have you ever noticed that there are no witnesses to ID Cordel as the real killer in the end? Sure, he stole the van and knocked a cop off of it, but that's as far as any cops seeing him goes. They proceed in a car chase and Cordel ends up impailed and drives off the peer, and later no body is found.
There was no indication that it was really Cordel, so why are the cops just buying the story and believing Bruce Campbell's character is innocent after all? Pretty dumb cops if you ask me.