By Alex Seitz-Wald 
While it’s often best not to engage with conspiracy theorists on their own turf, as you can probably never convince them , it’s worth setting the record straight on all the myths and phony evidence surrounding the Sandy Hook massacre.
We’ve rounded up every major piece of evidence we could find that leads theorists to say the “official narrative” of events “doesn’t add up” and provided the facts that show why these questions can be easily explained. We’ve ignored the empty accusations with no evidence to support them (it was the Jews !) and focused only on the theories that try to present actual empirical or circumstantial evidence.
Let us know if we missed any and we’ll add to it as more myths emerge. In no particular order, here is your comprehensive guide to disproving the Sandy Hook Truthers:
Why aren’t the adults sadder? “They aren’t behaving the way human beings would act ,” as conspiracy theorist Jay Weidner told fellow conspiracy theorist Jeff Rense on his radio show. Theorists have zeroed in on Robbie Parker, who they say wasn’t grieving hard enough for his slain 6-year-old daughter, Emilie. In one widely circulated clip, Parker laughs before stepping up to the microphone, and apparently someone says “read from the card ” (as in cue card) before Parker breathes heavily in anticipation of beginning a press conference. “This is what actors do to get into character ,” one popular YouTube video states. Rense and Weidner also take issue with the mourning of the school nurse, the family of slain teacher Victoria Soto, and others. “ALL ACTORS??? NO TEARS ,” wonders the author of SandyHookHoax.com on a page featuring videos with numerous interviews from the shooting.
Answer: People mourn in many different ways, sometimes all at once. As a recent Scientific American article  on gref noted, “oscillation between sadness and mirth repeated itself in study after study … Time and again, a grief-stricken person’s expression would change from dejection to laughter and back.” George Bonanno, a psychologist at Columbia University who studies grief, even developed a way to determine if this mourner’s laughter was genuine or merely a facade to hide grief — he determined that they “exhibited the real thing.” Scientists think this is part of our internal resilience mechanisms kicking in, because constant grief is simply too much for a person to handle.
What about Emilie? One of the most common myths circulated on message boards and in YouTube videos is that Emilie Parker  is actually alive. The “proof” is a photo purportedly showing her with President Obama when he visited the school after the shooting. Conspiracists know it’s Emilie because she’s wearing the same dress as the one Emilie wore in a family portrait taken before the shooting (an alternative theory is that the girl in the photo with Obama is her “double”). Other websites take issue with the family portrait, alleging it was Photoshopped  for some reason, pointing to the fact that the Emilie is making a “devil’s horns” sign with her hands and “making the devil’s horn hand sign isn’t easy. Try it yourself. Imagine getting a 3- and 4-year-old do it.”
Answer: The girl on Obama’s lap is Emilie’s little sister. It’s amazing that we have to say this, but sometimes younger siblings wear clothes passed down to them from older siblings, and sometimes siblings look alike because they are siblings.
For background on the issue see the following article from AlterNet