The story of Operation Ottawa, the cold case detection of John Cooper for two Pembrokeshire double killings: the Scoveston Manor murder of Richard and Helen Thomas in 1985 and the Pembrokeshire Coastal Path murder of Peter and Gwenda Dixon in 1989. Detective Chief Superintendent Steve Wilkins tells how he gathered a specialist team to review the murders, used cutting edge forensic techniques to prove Cooper's involvement in the crimes, and how the tv programme Bullseye led to a crucial identification. The dramatic timeline involves psychological profiling, intimidation by Cooper, the relationship between police and media in the arrest and the predicament of the victims' families during the long years when the cases remained unsolved. The combination of painstaking evidence gathering, new forensics, psychological profiling, and careful detection made Operation Ottawa the template for subsequent murder enquiries. Now, for the first time, the lead detective tells the story of how a vicious killer was brought to justice.