The Pembrokeshire double murders investigations spanned more than 20 years.
Below is a timeline of key events during the investigations.
22nd of December at Scoveston Park, near Milford Haven, the bodies of brother and Sister Richard (58 years old) and Helen Thomas (54 years old) were found following the discovery of a fire at the address. Both Richard and Helen Thomas died as a result of gunshot wounds. A murder investigation was launched and an incident room set up to manage the enquiry.
• Numerous media appeals were made including television and radio. Posters were issued and press releases featured in media publications (locally and nationally).
• Det. Chief Superintendent David (DM) Davies was the senior investigating officer and led the investigation.
• At its peak in 1986, there were 150 officers involved. The offence remained undetected.
2nd of July – Tim Dixon the son of Peter and Gwenda Dixon reports that his parents have not returned home following a camping trip in Pembrokeshire.
5th of July - the bodies of Peter (51 years old) and Gwenda Dixon (52 years old) were found concealed close to the coastal path near Little Haven at 3.30pm. They were last seen on Thursday 29th of June leaving their tent at Howelston Caravan park at approximately 9.30a.m 6th of July – Press conference called at Haverfordwest Police Station to announce the murder of Peter and Gwenda Dixon. Chief constable Raymond White and Det Chief Superintendent Clive Jones, leading the investigation.
10th of July – Press conference called at Haverfordwest police station. Timothy Dixon, Gwenda and Peter’s son, and Detective Chief Superintendent Clive Jones give interviews and make a public appeal. An artist’s impression of a man seen in the area who police want to interview is released. It is also revealed that the man used Mr Dixon’s cash point card at banks in the area.
18th of July – Police confirm that over 1,700 calls have been received from the public in relation to the investigation. But the cyclist who used Mr Dixon’s cash point card has still not been traced. 1990.
18th of June – on the first anniversary of the murders an operation is launched concentrating on the areas Peter and Gwenda Dixon visited in 1989. Residents and holidaymakers complete questionnaires with police officers over a two week period. The offence remained undetected.
6th March – In a field at the rear of the Mount Estate Milford Haven five young people all under the age of 18 years were confronted by a man wearing a balaclava brandishing a sawn-off shotgun, after making demands for money from all five he then subjected two of the female victims to serious sexual assaults. The offence remained undetected.
An incident room was setup at Haverfordwest Police Station - the senior investigating officer was Det. Supt Aldwyn Jones.
2nd of December – BBC’s ‘Crimewatch Still Unsolved’ programme features a reconstruction of the coastal path murders. It also repeated some footage used in the first Crimewatch appeal and an interview with the Dixon’s son Tim. The response to the programme was described as ‘excellent’ and information from over 400 calls was evaluated and led to the police following up lines of enquiry. 1998.
21st January 1998 - John Cooper was charged at Haverfordwest Police Station with a number of burglaries and an armed robbery (collectively known as Operation Huntsman), which occurred in North Pembrokeshire.
29th of January – Forensic and ballistics officers examine the home and surrounding grounds of the man arrested.
10th of December – John Cooper was sentenced to 16 years for armed robbery and 30 burglaries. 2006.
Feb – Operation Ottawa is formed. A small dedicated team of officers (who had no involvement in the original investigations) were commissioned to conduct a thematic review of material from outstanding undetected serious crime in the Pembrokeshire area, in particular to include the double murders of Peter and Gwenda Dixon and Richard and Helen Thomas, and also the robbery/rape offences that took place at Milford Haven in 1996. The team were given considerable support from the National Police Improvement Agency (NPIA) through access to advisors, scientists, profilers and psychologists. Financial support was also secured from the Police Standards Unit via the ACPO Working Group.
The team spent two years going through a painstaking process of the recovery, cataloguing and recording of all material from the investigations. In doing so, they identified statements and documents, which have detailed scientific and forensic processes that certain material was subjected to in order to identify forensic opportunities.
8th of November - Press Conference called at Haverfordwest Police station to outline the aim of Operation Ottawa and provide an overview of the current situation. A renewed public appeal is also made for any witnesses or anyone with any information in relation to the offences.
June - Cooper is produced from prison with the agreement of the CPS to be questioned about the two double murders and offences in the 1990’s. He was produced to Ammanford Police Station and interviewed over a four day period. 2009.
April 23rd 2009 – Ottawa receive the first phone call from LGC Forensics regarding significant forensic findings.
April/May – LGC forensics continue to make significant forensic discoveries relating to the above murders and robbery/rape. Consultation takes place between the SIO Detective Chief Superintendent Steve Wilkins and the CPS.
13th - 15th of May – John William Cooper is arrested, and following CPS advice is charged and remanded in prison for the murders of Helen and Richard Thomas at Scoveston Manor in 1985, the murders of Peter and Gwenda Dixon on the Pembrokeshire coastal path in 1989, a serious sexual assault and five attempted robberies in Milford Haven in 1996, after appearing in Haverfordwest Magistrates Court.
27th of May – Cooper appears before Swansea Crown Court.
21st of March – Start of Cooper trial at Swansea Crown Court – Postponed to October 2010 and then to 21st March 2011.
26th of March - John William Cooper found guilty of all charges, sentenced to life in prison.