I remember being really shocked when I learned the very successful mystery writer, Anne Perry whose books I've always enjoyed, helped her friend murder her friend's mother when a young girl in Australia. There's more about it HERE and, I am sure, elsewhere on the Internet.

Also, for an extremely good book, even though it's fiction, I would highly recommend reading What Came Before He Shot Her by Elizabeth George of the Inspector Lynley series. WCBHSH is about the young man who shot and killed Lynley's pregnant wife in the book just before it. What Came seems to me to be an excellent look into the socio-economic background of society and how a good kid trying their best can wind up in such a horrible situation as murdering someone.