Watch Real Crime UK online: Episode 16 Hunt For Mr Swirl

Interpol took the unprecedented step of launching a global public appeal for information after Canadian Christopher Neil published pictures of himself on the internet abusing children. Neil had camouflaged his face using editing software, making his features vanish into a swirl pattern. But he was quickly identified by Interpol experts who immediately began a manhunt. The detective who led the inquiry says of Neil's decision to publish pictures of himself committing abuse, "It's a badge of honour [among other paedophiles] ... your stock in the community goes up." The programme interviews Neil's brother, the woman who worked with Neil when they both taught in South Korea (she identified his unscrambled photograph) and Neil's transvestite boyfriend, who was with him when he was arrested in Thailand.

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