“While American and British forces conducted a series of drone strikes on members of the group, the F.B.I. sifted through thousands of the Legion’s followers on social media to figure out who had actually been inspired to take action. In the last two years, it has arrested nearly 100 people in cases involving the terrorist group.”
Source: One by One, ISIS Social Media Experts Are Killed as Result of F.B.I. Program – The New York Times