Rachel Nickell was brutally stabbed to death on Wimbledon Common in 1992. Following an extensive manhunt, police think they have the killer but after a year in custody, the trial collapses and it’s clear they’ve got the wrong man. Is there a psychopath still at large? How long before he strikes again?

As the police continue to hunt for Rachel Nickell's killer, they realise a spate of attacks might be linked. After sixteen years, advances in forensics and new discoveries, Police catch their man, Robert Napper. How was he able to hide in plain sight? And what other crimes might he have committed?