We focus on the part of the internet that most people don't know about.

It's called the dark web.

Undercover in the furthest corners of the dark web,

US special agents are on a mission to locate and rescue children from abuse.

Move in now.

Police!

From the BBC World Service, World of Secrets, the darkest web follows their shocking investigations.

Listen on BBC.com or wherever you get to your BBC podcasts.

So what we've found here is an old interview, a TV interview with my dad.

I've never watched this interview before

and I'm about to watch it with my dad.

What's your reaction been to the news

that the remains of your son

have probably been found by the police?

Well I...

It came as a shock.

I suppose I should have expected it,

but...

I was just hoping that something might...

You know, he might still be alive.

If these indeed are Vichel's remains, what will that mean to your life here?

I can't see how it's going to alter my outlook to my life here.

...