SERIAL killer John Cooper kept a collection of 500 sets to keys as mementos at the bottom of a cesspit, it has been reported.
The murderer is currently serving life for four murders in Pembrokeshire, Wales.
John Cooper currently serving life for four murders in Pembrokeshire, WalesCredit: Rex Features
The killer is said to have kept keys as mementos from his victimsCredit: Athena Picture Agency
John Cooper is a serial killer and burglar
Cooper, 76, shot siblings Richard and Helen Thomas at their manor house in 1985.
Four years later he murdered couple Peter and Gwenda Dixon, who had been on holiday in the area.
Cooper’s crimes led him to become one of the most notorious killers in modern Welsh history.
Cooper was given a full life sentence in the wake of his hideous crime wave, which was brought to an end by the detective work of Steve Wilkins and his Dyfed-Powys Police team after 26 years.
Mr Wilkins has now revealed how Cooper kept trophies from the victims to “re-live that control” he had over him.
The 61-year-old told The Mirror: “When they searched his house, they found 500 sets of keys hidden in the cesspit.
“The shorts which had DNA which led to his conviction, he stole from Gwenda Dixon when he murdered her.”
Cooper was also dubbed the Bullseye killer following his appearance on the hit show in 1990 around the time of the murders.
This appearance helped cold-case officers nail him 21 years later by matching him from the show to a sketch of the suspect.
He was behind a catalogue of crimes, including 30 robberies and violent assaults, along with the gunpoint rape of a 16-year-old girl and the sexual assault of a 15-year-old, also with a gun pointed at her back in 1996.
Cooper was sentenced to 14 years in 1998 for burglary and robbery and was due to be released in 2009.
But through a cold case review, he was arrested and convicted of two double murders and sexual assaults dating back to the 1980s.
He received a whole life order.
Cooper, who unsuccessfully tried to appeal his convictions in September 2011, is still behind bars in an undisclosed prison.
The investigation into Cooper was turned into a book and then a three-part ITV drama starring Luke Evans and Keith Allen.
Serial killer John Cooper, right, appeared on game show Bullseye in 1989
Cooper murdered Richard and Helen Thomas in 1985
The serial killer shot both Peter and Gwenda Dixon in 1989