The internet is no longer a place you log on and visit; it's where you live. The home of true crime is now online. The internet is the Wild West. And if you're not careful, you too could be caught in a Web of Lies.

Roo Powell is a woman on a mission to expose the dangers of and prevent online child sex abuse; with the help of her nonprofit team SOSA (Safe from Online Sex Abuse), she transforms into underage girls to engage with child predators and protect the most vulnerable.

How does a Northern Irish teen become one of the world's worst online child sex abusers? Victims, families and police share how catfish killer Alexander McCartney was caught.