John Cooper is a serial killer responsible for the murders of four people, Richard and Helen Thomas and Peter and Gwenda Dixon, and is at the centre of the police investigation currently being retold on ITV's The Pembrokeshire Murders.
The now 76-year-old was initially released from prison after 11 years on a burglary and robbery charge, only to be arrested a second time for the two double murders committed in the 1980s, as well as sexual assaults on two teenage girls, which he committed in 1995. He is now serving a life prison sentence at an undisclosed prison.
WATCH: Have you watched The Pembrokeshire Murders yet?
According to the BBC, at the time of his sentencing the judge, Justice John Griffith Williams, said: "[You are] a very dangerous man, highly predatory who, but for advances in forensic science, may well have continued to evade capture... The murders were of such evil wickedness that the mandatory sentence of life will mean just that. You are a very dangerous man, a significant risk of serious harm".
John was brought to justice through new DNA technology over 20 years after the initial murders, but was also spotted as a perfect match to an artist's impression of the murderer after the police managed to get hold of tapes of him from the exact same time taking part on the quiz show, Bullseye.
At the time, Detective Chief Supt Steve Wilkins said: "What we managed to do then was freeze John Cooper in exactly the same position as the artist's impression, and for me, it was like a tracing."
Cooper is currently serving a life sentence
Cooper attempted to have his conviction appealed in 2012, with the Lord Chief Justice telling the BBC at the time: "The defence case was the applicant had been wrongly convicted of the Huntsman offences and that he was not guilty of the present offences.
He is played by Keith Allen on the show
"The jury no doubt considered his [Cooper's] evidence carefully before deciding his guilt was proved. The application for leave to appeal against conviction was refused by a single judge. We agree with him. This renewed application will similarly be refused."
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