The worst crime?

I recently had a discussion with my friends about what they viewed as the worst crime that could possibly be committed. Personally, I presumed most would go for murder, but in fact, none went for it.
The suggestions were:
Arson
Torture
Blackmail
Abduction

My idea was rape; it causes physical agony and often mental damage. Sources:
http://www.cnn.com/2006/WORLD/africa/05/23/koinange.rape.war/index.html
http://en.allexperts.com/q/Rape-Counseling-1570/gf-raped-1.htm

Anyway, I was just wondering as to your views.
What do you think the worst crime that can be committed is?