I saw this horrible show on A&E recently about the connection between mass and serial killers and cruelty to animals. One of the kids who shot up his school in the '90's along with killing his mother before hand, first went out and killed his pet dog and wrote about it in his journey.
It was so sickening, what he did to a being that most likely loved and trusted him unquestioningly, that I can't bring myself to repeat it here but suffice it to say, no gun of any sort was involved.
This sicko creep would have found a way to inflict pain and damage on others if all weapons were banned. And that goes for knives, chop sticks, golf clubs, whatever.
A bunch of those kids were on psychiatric meds. Let me know if you want some links about it.