Quote from TheDudeofLife:
Maybe he came to America to have the opportunity to live out his fantasy to go on a Halo 2 style rampage. His country may not glorify violence, but he could have been exposed to things that do, which warped his mind. I would have thought gun laws in the United States would require citizenship to purchase a handgun.
How about this guy was born a psychotic killer. And psychotic killers would find a weapon regardless of the local laws.
Keep reaching....