JOHN COOPER was convicted of the murders of Richard and Helen Thomas and Peter and Gwenda Dixon as part of a nine-week trial in 2011. The murders had remained unsolved for more than two decades.

The two things which linked the murders with John Cooper were both forensic. A pair of shorts and a gun.

A Herald investigation has uncovered evidence that these forensics are no longer safe due to contamination of evidence whilst in police possession.

We have looked at hundreds of documents relating to the Thomas and Dixons murders in 1989 and have come up with a list of facts, most from police files, which make interesting reading, especially in-light of our findings regarding the forensic contamination.

The Herald believes that the link between the murders in 1989 and the IRA has not been investigated properly.

We have contacted the Provisional IRA Press Bureau in Dublin for a comment. We could write several pages about what we know so far, but here are the key points:

1. The day before the murders a yellow scuba diving boat with six men on board was spotted, but never traced, directly below the murder scene, the location of the only near-by landing stage

2. The area was confirmed to have an IRA weapons cache in November 1989 at the conclusion of a seven-week stake-out called Operation Pebble. Two men were arrested: Damien McComb and Liam O’Duibhir. They were each jailed for 30 years in December 1990.

3. Semtex from the cache, discovered near Newgale, was said by police to have been used in the bombing of the Royal Marines barracks at Deal in Kent in September, 1989. Police tried to question the pair over the murders, but they refused to cooperate.

4. Two men were seen heading towards the location of the Dixons less than an hour before the murders. They were in the Crimewatch reconstruction, but they were never traced. They would have been the last people to see the Dixons alive.

5. Local’s told police that the Dixons had interrupted criminal activity and had been taken to Talbenny Cottages before their deaths.

6. In Talbenny Cottages, the nearest dwelling to the murders, police found signs of a disturbance, but nothing had been taken. They also found a receipt for tickets purchased for the Liverpool to Belfast ferry dated June 28, 1989, a restaurant receipt from Belfast, and information pamphlets relating to accommodation in Belfast.

7. The cottage had been purchased in early 1989 by Irishman Joseph Murphy. This is assumed to be a pseudonym. On July 3, 1989, the same day the Dixons were reported missing, Semtex bombs went off in Belfast Harbour Airport.

8. In woodland near Pontargothi in Carmarthenshire, just off the A40, police recovered a bag containing blood-stained clothing and a handkerchief. Forensic tests concluded that the blood did not belong to Peter Dixon, Police weren’t able to say definitively that the blood did not belong to his wife, Gwenda Dixon.

9. The Dixons bodies were found in an area off the footpath where a military-style hide had been built, including uprooted re-planted bracken. This is taught in SAS training manuals. The bodies were therefore found in a purpose-built hide of some kind.

10. Mr Dixon’s bank card was used in Pembroke just hours after the murder by a man on a bicycle. He tried to withdraw £37 – possible in Irish cashpoints at the time, but not possible in the UK as pound notes had been recently discontinued.

11. The man on the bike, described as a drifter, thin, and scruffy was seen by multiple witnesses in the weeks leading up to the murders in Marloes, Martin’s Haven, Dale and along the coast path and was said to have the appearance of a person who had been sleeping rough.

12. Unusually, this man was even seen on Dale airfield by learner drivers – the place where Peter Dixon, a radio-HAM, went to send a radio message to a friend from his in-car low band radio.

13. The murders could not really be said to be a robbery as Mr Dixon’s most expensive items – his camera and binoculars were not taken but left at the scene, along with both Mr. & Mrs. Dixons’ watches. The cashpoint card was used – but it was not unheard of at that time for people to keep PIN numbers written down in their wallets especially when they had many cards – Mr Dixon carried ten or more.

14. Richard Thomas from Scoveston Manor reportedly told people close to him that he had received threatening phone calls in the weeks before the death of him and his sister. He said the phone calls were from people claiming to be the IRA.

15. Shotgun cartridges were removed from both scenes – the sign of a professional – Police reports suggest that the gun found near Cooper’s home was not the gun used to kill either couple as the wads from the gun did not match when the weapon was test fired.