What leads a young person, living what seems to be a "normal everyday life" in the West, to join an extremist group?
And what can you do to bring them back?
The BBC talked with one young British woman who was recently contacted by ISIS recruiters. She preferred not to use her name, but she did talk about what first got her interested in groups others might view as radical.
It was the news about three teenage girls, gifted students in east London who slipped away in February to join ISIS.