DIANE SAWYER SPENDS ONE YEAR INVESTIGATING HOW ISIS TARGETS VULNERABLE, YOUNG AMERICANS ONLINE

Special Report Focuses on Next Phase of ISIS: Shifting Away From the Battlefield Overseas and Into American Homes

'20/20' Features Exclusives With American Teenage Recruits, Former ISIS Members and Heartbroken Parents Turning In and Tracking Down Their Lost Children

A Special Edition of '20/20' Airs on Friday, November 3 (10:00-11:00 p.m. EDT), on ABC

On Halloween, October 31, 2017, 8 people were killed and 12 others injured in the worst terror attack in New York City since the September 11 attacks. Since 2014, there have been 13 violent ISIS-inspired attacks in the United States motivated in part by ISIS propaganda online, killing more than 70 people and injuring nearly 500. With 1,000 investigations and 146 federal cases across the country, young Americans from different backgrounds and religions are charged with trying to join the forces of terror. Of those, 40% are not born Muslim, 89% are male, and the most common age is 20 years old - according to the Center on National Security, Fordham University School of Law.

For more than one year, ABC News Anchor Diane Sawyer and a team of producers investigated how ISIS targets young Americans online and recruiting them to join ISIS. Sawyer reports on who these young people are, what makes them vulnerable and why they want to become terrorists - is it for politics, religion or something else? The special edition of "20/20" features exclusives with teenage American recruits, former ISIS members and heartbroken parents who have had to turn in and track down their children. Sawyer goes inside the investigations with law enforcement to analyze surveillance video and tapes. She also reports on the efforts of technology companies to counter ISIS propaganda on social media and encrypted sites that flourish on the dark web.

The Americans profiled in the hour include:

· The teenage son of a retired Marine captain from a Christian home in North Carolina who went from winning trophies at school sports to planning a terrorist attack after connecting with a top ISIS recruiter;

· Three teenage girls who secretly booked a flight to join ISIS after being seduced online with a promise of paradise;

· A couple from Mississippi - an honor student who was a soccer player and his pre-med cheerleader Baptist girlfriend - who tried to join ISIS.

The Diane Sawyer special edition of "20/20" airs Friday, Nov. 3 (10:00 - 11:00 p.m. EDT), on ABC.

David Sloan is senior executive producer.