How conspiracy theories in the US became more personal, more cruel and more mainstream after the Sandy Hook shootings

  Conspiracy theories are powerful forces in the U.S. They have damaged public health amid a global pandemic, shaken faith in the democratic process, and helped spark a violent assault on the U.S. Capitol in January 2021.

  These conspiracy theories are part of a dangerous misinformation crisis that has been building for years in the U.S.

Analyzing online posts could help spot future mass shooters and terrorists

  In the weeks following two mass shootings in El Paso, Texas, and Dayton, Ohio, police forces across the United States made more than 20 arrests based on threats made on social media.

  Police in Florida, for example, arrested an alleged white supremacist who, police said, threatened a shooting at a Walmart. Richard Clayton, 26, allegedly posted on Facebook, “3 more days of probation left then I get my AR-15 back. Don’t go to Walmart next week.”

  People who are contemplating, or are even planning, serious crimes rarely make such clear public declarations of their intent. However, they might leave clues that, if properly understood, could offer opportunities to avert tragedy. We have teamed up with computer scientist Anna Rumshisky to collect and analyze more than 185,000 words of extremist or hateful narratives published online by people who have then gone on to commit large-scale shootings or terrorist crimes.

Gene Policinski: Fear after violent incidents imperils our core liberties

  At various times, every American likely has wished for less of some things that the First Amendment protects. Less hateful speech. One less noisy protest group. Or maybe even the swift departure of a media outlet or personality whose stance or voice is just grating on a personal level.

  But for the most part, those wishes come and go – or the targets do, as media fortunes or political trends wax and wane.