Uncovering what happens inside 764’s chatrooms and its devastating toll on victims and families who are caught in the web of a network so dangerous, global law enforcement can barely keep up.

We meet a Canadian mother, whose daughter was drawn into the group’s grip, revealing how 764’s tactics push families to the brink and leave no one untouched.

Written and Produced by Jo Palmer.

For information and support on issues discussed in this series, visit bbc.co.uk/actionline.