Could there be a reason why Illinois and Wisconsin seem to breed some of the most notorious serial killers?

While reading the encyclopedia of serial killers I noticed that Illinois is the smallest state that produces a large amount of serial killers. As of why no one will every really know. But out of the ones you named all were abused by a parents except Dahmer who said he was ually abused by a neighbor at 8. There parents were the fault for most of them. I dont think anyone will ever be able to figure out why they all did things or came from Illinois, unless the ratio of child abuse is higher there.