I don't believe ghost's are from a person..........but are a result of the actions of that person when they were alive..... The more evil an action was demonic spirits would be present....they sit around laughing at the person doing the act...imagine them sitting there watching as a human hacks a body into pieces.. The demons sit there and say to themselves...look at the stupid humans doing our masters work.. When stuff like this happens this delights the stupid demons and they like that area..