- Texas shooting suspect appeared to have pledged support for ISIS
- Peter Bergen: Several dozen Americans have backed ISIS, most of them young and active on social media
Peter Bergen is CNN's national security analyst, a vice president at New America Foundation and a professor of practice at Arizona State University. He is the author of "Manhunt: The Ten-Year Search for bin Laden -- From 9/11 to Abbottabad." David Sterman is a program associate at New America.
(CNN)Elton Simpson -- one of the gunmen who opened fire Sunday at an event in Garland, Texas, that was celebrating cartoonists who had drawn pictures of the Prophet Mohammed -- appears to have declared his allegiance to ISIS in a tweet before the attack. Simpson also apparently had online ties to a British ISIS recruit believed to be in Syria.