In June 1881, Percy Lefroy Mapleton murdered Frederick Gold aboard the Brighton Express, then tried to pass off his own suspicious injuries as the result of an attack by the real killer. This History Hit documentary from the History Hit Network traces Mapleton's life as a self-styled fantasist chasing money and status, partly to impress a well-known actress, and follows the botched Scotland Yard investigation that ensued once his story fell apart. The case became a media sensation, with newspapers publishing an early published likeness of the suspect that helped the public spot him, a moment the film credits as the launch of the police sketch as an investigative tool. Historians walk through the train carriage crime scene, the forensic gaps investigators struggled with, and the manhunt that gripped Victorian Britain before Mapleton's eventual capture and trial. The film treats the case as both a true-crime story and an origin point for a policing technique still used today.