Undercover Police: Hunting Paedophiles - Channel 4 TV documentary spotlights Kent cops chasing sex offenders | Updated: 14:06, 09 February 2021 A convicted paedophile arrested during a police sting and another hunted in Margate are just some of the sex offenders highlighted in a television documentary this evening. Graham Marshall had bought a £132 rail ticket so he could have sex with a 10-year-old girl. Detectives try to track down another suspected paedophile who has scrawled a message on a wall inside the gents' toilets on Margate seafront. Picture: Tony Flashman But before he could board the train, undercover cops raided his home and arrested him.