Well, there's a whole literary genre - murder mysteries - that encompass everything from the morbidly gruesome to fantastically tame...think Agatha Christie. Kids are exposed to 'whodunnit' type conundrums at school too (the ones like there was a man found dead in the room with a goldfish, how did he die?) - so hmmm, while it's not my choice of topic it could be really engaging to some kids. My DD tells me that last year one of the teachers with 9 & 10 yr olds had them write spooky stories, and the murder theme came up in a lot of those stories.