How heartless does one have to be to do something as atrocious as this?

Totally, totally disgusting and without morals! So much of the news in the world, however, you question the same way, "How could anyone do this?!" WHAT does go through a "person's" mind to actually commit something this horrible. I cried when I heard on the news last night and didn't get the whole report, but enough to hear teens shot in New Jersey; 3 boys walked right up and shot one in the face and made other 3 kneel against a wall and shot them in the back of the head! Oh, dear God, why would they?! The one caught is 15 years old! Where and how does it stop?!