I don't give a flying f--- if civilians knew of the bomb. Nothing short of a direct threat from armed civilians justifies slaughtering them.
Good movie for you to review.. RULES OF ENGAGEMENT....
There is no evidence yet released that anyone was slaughtered.
In fact, they will not even have bodies, if you believe this morning's news. The family will not permit them to be exhumed.
Let's determine: (1) That these GI's actually killed someone, and (2) That there was no battlefield explanation that mitigates the killing.