Denver using case of 3 Denver teens as chance to study ISIS recruiting methods , officials say . The girls skipped school and planned to fly to Turkey to join ISIS , authorities say . U.S. spy chief says WhatsApp uses such platforms as WhatsApp and ISIS .
U.S. using case of 3 Denver teens as chance to study ISIS recruiting methods , officials say . The girls skipped school and planned to fly to Turkey to join ISIS , authorities say . UK spy chief says ISIS uses such platforms as Twitter , Facebook and WhatsApp .