Retribution coming

In this fourth book, our main character, sheriff duke moran, tracks down a serial killer who has a very good reason to want retribution. the killer is going from one place to another, taking out his revenge all across the u.s. a local resident of black crow in northern wisconsin has been receiving letters from a mysterious sender. the sender had broken into their home and hung the family cat, which he had gutted, and then hung from the ceiling in the living room. the letters said he would be back to visit them in the future. once duke figures out who the killer is, he gets the fbi involved.there was also a trial for two brothers who are accused of killing two girls. someone starts killing off the jurors in the trial, and sheriff moran needs to catch the killer before all the jurors are gone.