There's something wrong with this story, and I don't mean it's validation.
First, if you're in a war-zone with a gun, you're not US troops and you're not UN, bye. No remorse for the kid here.
A gun isn't going to buy that teenager any protection against either US or Al-queda, and I see absolutely no reason not to shoot-to-kill if someone with a gun is approaching a house with your allies inside. My question is, why not take another shot and end the persons suffering? Dying and moaning for 20 minutes, people with guns and knifes all around. If you're shot in the head, chances are you're not going to be telling where any other terrorists are, you're not going to be any help to intelligence information.
I do wonder if there's something more to this story than the reporter is telling, if this is really a war-crime (which is a crock of shit), why didn't it come out until now? War crimes are big news, not something you wait 3 years to publish/talk about, especially with children involved. Lastly, for those of you who mentioned soldiers dying in Iraq after they signed up for it, here's another case of a person who didn't have to go, didn't have to put himself in danger, but he did and now he's suffering for it. What the fuck did he expect to see over there, unicorns and roses?