A serial killer convicted 12 years ago for two double murders in Pembrokeshire has applied to have his conviction reviewed.

John William Cooper, also known as the Bullseye Killer, was found guilty of four murders by a jury at Swansea Crown Court in May 2011.

He was also guilty of raping a 16 year old girl and sexually assaulting her friend.

Cooper robbed, burgled, raped and murdered his way across the Pembrokeshire countryside with a balaclava in his pocket and a sawn-off shotgun strapped to his back and hidden under a coat.

He blasted to death holidaymakers Peter and Gwenda Dixon, aged 51 and 52, as they enjoyed a last walk along the Pembrokeshire Coastal Path in June, 1989 "for a pitiful amount of money".

Four years earlier he had shot to death millionaire farmer Richard Thomas, 58, and his sister Helen, 56, after they caught him breaking into their home at Scoveston Park near Milford Haven.

And in 1996 he held up a group of five teenagers at gun point as they played in a field, raping one, indecently assaulting another and trying to rob all five. Police believe he was looking for more burglary targets at the time.

Cooper, of Spring Gardens, Letterston, was convicted following a cold case review, launched in 2007.

Advances in forensic techniques linked fibres from gloves found at his home and hidden in hedges nearby with all the crimes.

They also found a spot of marketing executive Peter Dixon's blood underneath paint on one of the barrels of Cooper’s gun and DNA evidence connecting him with the Dixons on a pair of shorts.

Cooper was branded ‘a very dangerous and evil man’ and was jailed for life.

The cold case review and subsequent conviction was the subject of hit ITV drama The Pembrokeshire Murders, starring Luke Evans, in 2021.

It has been revealed today that Cooper, 78, has applied to the Criminal Cases Review (CCRC) Commission to look again at his case.

A CCRC spokesperson said: “An application to review this case has been received.”

The CCRC looks into criminal cases where people, who have already lost an appeal, believe they have been wrongly convicted or wrongly sentenced.

The CCRC will launch a fresh appeal, if strong new evidence or an argument that makes the case look different, comes to the fore.

The independent body will send a case back to the appeal courts if such information is forthcoming.

Dyfed-Powys Police confirmed that it had been notified of Cooper’s appeal.

“We have been advised that an application for an appeal against conviction has been lodged by John Cooper with the Criminal Cases Review Commission (CCRC),” said a spokesperson.

“Heddlu Dyfed-Powys Police will comply with our obligations in any judicial process.”

The spokesperson added that it would be inappropriate to provide specific comments relating to the application made by Cooper at this time.