I read a longer account that said that some of the bodies that were shown to the reporters appeared to have been burned, in some cases, or to have major burns on parts of them. They seem to have been whole, however, so it doesn’t sound like it was a grenade or anthing, but it doesn’t sound like it was a shooting either.
The details are very unclear, and I certainly wouldn’t consider it unthinkable that the Muslims themselves might have staged the attack, if any. And it is definitely not unthinkable that they’d blame the US for an attack by another group, such as their beloved Taliban (which is very fond of killing women and children).
Until I have a name of a US soldier who did this, I will assume indeed that it was a Taliban member disguised as a US Soldier.