I have seen some FB posts that seem 100% sincere claiming that it was a hoax... I didn't completely understand the basis of the claim but it was something about seeing a picture of a little girl who appeared to be one of the girls who was shot, wearing a similar dress but with a different family? Like, "see, here she is in her real life with her real family in this picture, not with that fake dad who fake cried on the news"??
The one I saw was from a hard-core conspiracy theorist. Never in a million years would I believe something like that could be pulled off without someone spilling the beans, though, even if I actually thought the ebil govm't had reached the level of disgusting needed to hatch such a plot.