My bad. I was thinking of In Cold Blood
by Tuman Capote. In Broad Daylight
by Harry MacLean is about vigilante justice in Skidmore, MO. Perhaps not a good read right now
Any of the books by Darcy O'Brien are great reads and can illustrate that anyone can be a victim. They're true crime as well, so it's not pro-gun propoganda. He does a really good job of showing that psychopathic homicidal maniacs can look surprisingly normal. They're easy reads and entertaining, so you don't even realize you're getting a message.