Dozens of people in the U.S. are engaged in conversations with overseas supporters of ISIS that the FBI cannot monitor, FBI Director James Comey said Thursday, NBC News reported.
Comey has been warning for months that when ISIS supporters find someone in the U.S., through messages on social media, they then employ software that encrypts their communications, making it impossible for the FBI to follow them, even with a court order.
While Comey has discussed the "going dark" challenge before, his comments Thursday represent the first time he has put a number on the size of the problem. Over the past three years 250 people have traveled to areas controlled by ISIS from the U.S.
