"Elliot Rodger didn’t become a killer because he was a misogynist; he became a misogynist because he was a killer. Just like Eric Harris didn’t become a killer because he loved violent video games; he loved violent video games because he was a killer. Just like Adam Lanza didn’t become a killer because he loved guns; he loved guns because he was a killer."
http://markmanson.net/school-shootings
Good read.
I ran across this in my gogle-fu, and is an interesting watch. It's from 1982, and I will warn there is a "anti gun" message at the very end (not Michael Morrish), but it does offer insight into mass murders, serial killers, etc. Note the length: 1.5 hours.
Edit-there are graphic parts, so keep the youngin's away.
http://www.youtube.com/watch?v=lH-knbqmXn0
Nuts will always be nuts. The difference is the tree they fall off of....