John Cooper, who is currently serving life in prison for the murders of Gwenda and Peter Dixon, and Richard and Helen Thomas, was married when he was being investigated for these crimes.
In 2009, Cooper was released from prison after serving 11 years behind bars for robbery and burglary. Little did the police know at the time, he had shot and killed brother and sister Helen and Richard in 1985, before setting their house alight.
He also murdered husband and wife Peter and Gwenda on coastal path in Pembroke, after they came from Oxfordshire for a holiday.
But in a bizarre twist, his wife Pat died on the night that he moved back into the family home after being allowed parole. Detective Chief Superintendent Steve Wilkins, the man who.
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