The pursuit of Christopher Halliwell by Detective Steve Fulcher has been one of the biggest crime stories in recent years, captivating the public's attention. Spanning more than a decade, multiple murders, two much-publicised trials and one irreparably damaged career, it is a story of the dogged pursuit of a serial-killer by a police officer determined to get justice for the families of his victims. From the moment the case of a missing 21-year-old girl named Sian O'Callaghan landed on the desk of DCI Fulcher, the hunt was on. What unfolded over the following five days was a game of cat-and-mouse of the utmost stakes, characterised by the painstaking and relentless pursuit of a killer by a seasoned detective with decades on the force.