Elizabeth Williamson of The New York Times speaking about her new book, "SANDY HOOK: An American Tragedy and the Battle for Truth."

At 9:35 a.m. on the morning of Dec. 14, 2012, a 20-year old man shot his way into Sandy Hook Elementary School in Newtown, Connecticut, with two rifles and a handgun. He then brutally turned those guns on those inside the school, murdering 20 1st graders and six educators before turning the gun on himself. Police later discovered he’d killed his mother earlier in the day.

There have been more than 1,300 school shootings in the U.S. since 1970. The tragedy of Sandy Hook, of course, was the worst mass shooting at an elementary school in American history. But what unfolded afterward was also a tragedy: conspiracy theorists who not only propogated lies about Sandy Hook through social media, but insidiously harassed the parents and families of the survivors, threatening them online and at their homes in the months and even years that followed. Studies show that at various points as many as 20% of Americans believe that mass shootings like Sandy Hook are hoaxes perpetrated by either the government or some shadow, clandestine entity — thanks to the spread of false accounts and the failure of social media platforms to remove them.

Elizabeth Williamson's new book is a compelling, engrossing account — not of the shooting at Sandy Hook, but about what happened in the hours, the days and the months that followed as conspiracists like Alex Jones of InfoWars used their platforms to incite and enrage millions of listers and followers — and share lies about what happened on that December day.