John William Cooper (born 3 September 1944) is a serial killer from Milford Haven, Pembrokeshire. On 26 May 2011 he was given four life sentences for the 1985 double murder of brother and sister Richard and Helen Thomas, and the 1989 double murder of Peter and Gwenda Dixon. Cooper was also sentenced for the rape of a 16-year old girl and a sexual assault on a 15-year-old girl, both carried out at gun point, in March 1996, in woodland behind the Mount Estate, Milford Haven.

Cooper had a history of crime, including 30 robberies and violent assault. He also appeared on the TV game show Bullseye in May 1989. Footage from the show was later used as evidence against him, comparing his image with a sketch of a suspect in the Dixons' murder. Cooper was sentenced for 14 years in 1998, (served 10 years) for burglary and robbery, enabling the police to collect further evidence against him. He was released from prison in January 2009. Through a cold case review, and subsequent developments in DNA and forensic science, in April 2009 the police were able to identify Cooper's shotgun as the murder weapon. He was arrested in May 2009 and was convicted in May 2011 for the double murders and sexual assaults.

Film Duration: 46 min .