A review of evidence surrounding the conviction of David Morris for the brutal Clydach murders more than twenty years ago has led to “significant findings as a result of analysing key forensic evidence”, according to South Wales Police.

Morris, who died in prison in August, was convicted of the murders of Mandy Power, her two daughters Katie and Emily and her mother Doris Dawson, the bodies of whom were found at an address in Kelvin Road, in the Clydach area of Swansea, in June, 1999.

Mr Morris’s family and friends always maintained his innocence and in November last year legal representatives of the convicted killer asked South Wales Police to release various exhibits from the investigation into the murders, which the force has described as “the largest and most complex ever undertaken by a Welsh police force”.

Following the request, South Wales Police appointed a senior investigating officer and an independent forensic laboratory to oversee a forensic review of the case material. This process - called Operation Dolomite - was led by detectives Steve Carey and Ian Ringrose, supported by police forensic expert David Lloyd, all of whom are from Devon and Cornwall Police, while an independent forensic science laboratory, Cellmark Forensic Services, was commissioned to carry out forensic work.

Following Morris’ death on August 20, his family gave permission for a blood sample to be obtained in order to allow forensic examinations to take place. According to police, the analysis of key forensic evidence has led to a scientific link between Morris and a sock.

Scientific examination of the sock, widely accepted as being used by the offender during the killings, identified the presence of a “mixed Y-STR profile”, which is potentially linked to Morris. While the presence of a link to Morris and the profile has been identified, police said “the science cannot determine how or when this profile was transferred onto the exhibit”.

However, they added that “the conclusion of scientists is that it is more likely that Morris contributed to the DNA profile found on two different areas of the blood-stained sock than if he did not contribute DNA to them”.

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Assistant Chief Constable David Thorne, of South Wales Police, said: “The decision to carry out an investigative assessment did not constitute a reopening or reinvestigation of the murders, nor did it demonstrate any lack of confidence in the conviction of Morris and the subsequent case reviews. Morris was convicted unanimously by a jury on the strength of the prosecution case and independent reviews by the Criminal Cases Review Commission have never identified any evidence which would determine the conviction to be unsafe.

“However, the advancement of forensic technology has provided the opportunity for evidence-based answers to some of the questions which have been raised about forensic issues in this case, along with other matters raised by the BBC Wales documentary ‘Beyond Reasonable Doubt’. The appointment of Steve Carey and his team has ensured the review has been conducted with a layer of independence.

“My team has carefully examined the issues raised and subject to the terms of reference for Operation Dolomite.

“In the opinion of the forensic scientist regarding these results - which were obtained from samples extracted from two separate areas of the sock at the time of the original forensic examination - it is more likely that David Morris (or a close paternal-line male relative of his) contributed DNA to them than if he did not.

“In relation to one sample, the lead forensic scientist has stated to me that in his opinion the low-level and incomplete mixed Y-STR result is as would be expected if Morris had contributed DNA to it. For another person to have contributed to it, the components must match by chance.

“The scientist would have a very low expectation of selecting a male individual at random from the Western European population having components in their Y-STR profile being represented to the same extent as those in the Y-STR profile of Morris.

“To test this, an evaluative tool developed by Cellmark Forensic Services showed that from a dataset of 9,357 Western European males, no-one is represented to the same extent as the component in the Y-STR profile of Morris.

“It should be noted that the results do not allow the scientist to interpret how the DNA got onto the sock and therefore whether this was through directly touching the item or indirect transfer but the identification of this link has been possible due to the development of technology which would not have been available to the original investigation team.

“This is significant as the sock was recovered from the murder scene and it was widely accepted that it was used by the killer.

“The outcome of the forensic assessment and completion of further actions have not established any information that undermines the conviction of Morris. In my view, as the independent senior investigating officer, the new findings from the samples taken from the sock support the existing evidence that originally convicted him.”

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The operation also investigated accounts provided by two witnesses who featured in the BBC documentary, who have since been interviewed by officers. That evidence was shared with the Crown Prosecution Service, and police said that none of the information gathered undermined Morris’ conviction.

Mr Thorne added: “Notwithstanding the fact that Morris has been convicted based on overwhelming evidence against him, South Wales Police has shown a commitment to providing evidence-based answers to the issues which have been raised about this case over many years.

Mandy Power with daughters Katie and Emily
Doris Dawson

“This commitment has now resulted in a forensic link between the convicted killer David Morris and an item of great significance which was recovered from the murder scene. South Wales Police commissioned the review in the hope that we could in some way provide closure for those most affected by the murders. In particular, those who lost three generations of the same family and have had to revisit those painful memories time and time again over the last two decades.

“The findings from Operation Dolomite will be shared with the Criminal Cases Review Commission to complete the due process and demonstrate transparency. However, in the knowledge of the conclusions drawn from this review, South Wales Police would like to show respect to the family and those affected by these terrible crimes by finalising this case.

“Our thoughts as ever remain with the family of Mandy Power, her children Katie, aged 10, and Emily, eight, and her 80-year-old mother Doris, who still experience such painful memories even to this day.”

The outcome of the the review and its findings has been communicated to the families of the victims, and to the family and legal representatives of Morris.