"This happened a number of days ago, as many of you already know. The kid was an 18 year old Bosnian immiigrant. The Bosnian community is suffering because of this one person's actions. A lot of people have focused a lot of anger toward these people, and it is not even their fault."
Whose fault was it?
Go figure. The kid made the decision. We have no idea why his trigger tripped. Any ideas in this area at this point are strictly speculation. Speculation is defined as conjecture, or opinion. There isn't even empiracle evidence to provide an educated guess.