More than two years after the self-proclaimed Islamic State burst on the scene, it is still difficult to quantify just how big the threat is in this country. Counterterrorism officials say nearly 200 Americans have traveled to Syria and Iraq, are thinking about doing so or have returned to the U.S. after spending time there.
NPR has learned that number of returnees in this country is nearly three dozen — but their cases remain sealed.
At the beginning of the year, FBI Director James Comey announced that the bureau had open investigations of supporters of ISIS in all 50 states.