A teen who opened fire in a Colorado high school this week was active on a so-called "violent gore" site months before the attack, the Anti-Defamation League said in a report released Friday. Colorado ...

The attacker, who shot and wounded two students, reposted a photo of a revolver and a box of ammunition two hours beforehand, research by the group's Center on Extremism shows.

We feel like people don’t even know that this is going on,” said Oren Segal of the Anti-Defamation League. “We need to understand there are these terrible places online.” ...