BBC Sounds, music radio podcasts.

It's Beyond Today from BBC Radio 4, I'm Matthew Price.

Every weekday we ask a big question about a big story. Today what happens when pedophile hunters catch your dad?

Hello, mate. You're a range to meet a 14 year old boy here today for sex? Yes you have

mate. Do you want me to get the stuff out to show you? I've got all the chat log

there buddy. So we're screen-shotted, it's all there.

The police are on their way right now.

You're joking.

I'm a pedophile, I'm not mate.

It's what I do. I'm afraid you're under a citizen's arrest, so I'm not going to let you go anywhere, okay?

No, mate, you're under citizens arrest I can use

for something. That is a pedophile hunter. They're people who actively track down

paedophiles. Sometimes their evidence leads to prosecutions, but sometimes their actions can end up hurting innocent

people, which is what happened in the story you're about to hear, and it's a story that two of the BBC's journalists wanted to tell us about.

I'm Katron I am a reporter on the Victoria Derbyshire programme. I'm Andy Smythe I'm a

senior producer on the Victoria Derbyshire programme and a filmmaker.

It was a Sunday morning in 2015 and I was looking at my Facebook account.

A video popped up on it with a man being confronted by Peter

File Hunters. He'd arranged to meet a 15 year old girl for sex and they were confronting

him and they told him that he'd be arrested.

Now this was a man I knew.

I knew him personally.

...