Why is Hollywood and any other type of media so obsessed with..?

Let's face it, people find crime interesting and murder to be the most interesting. People still try to figure out who Jack the Ripper was, who killed the Black Dahlia, etc. People still talk about and dissect the cases that most shocked and appalled them. I'd say the fascination with murder is little different than the fascination with the horror genre and other macabre things.