First, I wouldn't consider this horror as so many lists that it's on suggests it is; so if you're thinking this is going to be some nightmare fuel, this isn't that. Though who am I do tell you what haunts you, everyone's triggers are different. What this very much reminds me of, is a really great true crime podcast or documentary. I think it's well done and told from a very wholesome place by a person that was there during the height of the crimes and put themselves in the middle of it. The characters were fleshed out very well and you can feel the sense of community which really adds to the feel of it all.
If you have a first edition, get your hands on a copy with the afterword in it, that's important information to have was a great addendum to the story, I can't imagine feeling "finished" without it. I will for sure be reading the next story "Making the Boogeyman" and of course everything else by Mr. Chizmar, he's got an interesting talent for writing conversationally which feels very natural. I'm definitely a fan!