I also think there's a good chance that the sniper is some way connected to the child.
I don't think it's an accident that the victim was thirteen. Thirteen is the age of accountability in Christianity and for the bar mitzvah in Judaism. I think the sniper used a thirteen year old so he could rationalize that he was shooting an adult instead of a child.
I also suspect that to know this boy was thirteen, he had to have some passing knowledge of the victim's family. He may even have chosen him because he knew the kid would be getting there early when he'd have a pretty clear shot.
I'm betting the sniper is black muslim and probably connected to al Fuqra.
Parts of your reply are those gnawing things that many of us have had since the sniping began:
I think this is the most telling aspect that marks this as suspected terrorism.
That was the first thought that entered my mind when I heard about this.
Second you posted, I'm betting the sniper is black muslim and probably connected to al Fuqra.
Those of us who know the relationship fo the Black Muslims to the al Fuqra thugs and on to al Qaeda will not be surprised if what you posted here is the reality.
Alternately, it could just be that at 100-200 yards, it's hard to tell the difference between a 13-year-old and an adult