The families then went to the FBI , which intercepted the girls at the Frankfurt airport . 3 Colorado girls are killed on their way to the Middle East , allegedly to join ISIL . Their families alerted authorities , who were able to find them in Frankfurt airport . Peter Bergen : Police often spot signs of radicalization and alert authorities . More terrorist plots disrupted by media than by controversial NSA surveillance .
3 Colorado girls are killed on their way to the Middle East , allegedly to join ISIL . Their families alerted authorities , who were able to find them in Frankfurt airport . Peter Bergen : Police often spot signs of radicalization and alert authorities . More terrorist plots disrupted by media than by controversial NSA surveillance .