The family of four people murdered in a crime that shocked South Wales have called on supporters of the man convicted of the killings to accept his guilt.

David Morris was found guilty of murdering Mandy Power, her two daughters, Katie and Emily, and her mother, Doris Dawson, in Clydach, near Swansea, in June 1999.

All four had been bludgeoned to death with a pole before their house was set on fire.

The former builder was jailed for a minimum of 32 years, having been convicted for a second time of their murders in 2006. He died in prison in August aged 59.

Campaigners had spent years calling for his release from prison, attempting to shed doubt on the integrity of the original investigation.

Last month, South Wales Police said forensic evidence unearthed during a review of the Clydach murders links Morris with a blood-stained sock found at the crime scene.

Following a request in 2020 by Morris’s representatives for the release of certain exhibits, the force agreed to appoint an independent senior investigating officer and forensic laboratory to oversee a forensic review of the case material.

Police say the examination of a sock widely accepted as having been used by the offender during the killings identified the presence of a mixed Y-STR profile that links Morris, or a male relative of his paternal lineage, to the crime scene.

Scientists have said it cannot be determined how or when the profile was transferred on to the sock, but the DNA is more likely than not to be Morris’s.

Police say accounts provided by two witnesses who featured in the BBC documentary Beyond Reasonable Doubt were also looked into, but the information gathered did not undermine the case against Morris.

In a statement, Ms Power’s family accused supporters of Morris of a campaign of “misinformation to hide the truth”.

“The loss and grief our family went through and continue to go through is heart-breaking and affects so many aspects of lives. No family should ever go through what we have and still do,” they said.

“It hasn’t been helped by the constant campaigns, protests, incorrect media reports, make-believe books and TV programmes that have mislead some of the public into believing Morris is innocent.

“These have blatantly ignored proven facts and replaced them with misinformation to hide the truth.”

The family said after Morris’s original conviction he won a retrial on the basis of a conflict of interest by a defence solicitor.

“The retrial took place and we again had to look at Morris and listen to lie after lie,” they said.

“Again, Morris was found guilty. Sitting through both trials and having to listen to what our family went through that night was heart-breaking beyond belief.

“Scientific testing has come a long way in the last 22 years and in October the police confirmed there was scientific evidence of David Morris on the sock.

“Sadly, Morris’s family and supporters are refusing to accept these latest findings done by an independent forensic laboratory, which is what they called for.

“We now feel that it is time that they accept that Morris murdered our family and finally let them rest in peace.”

The tragic events that saw the murder of a family-of-four prompted the largest and most complex police investigation ever undertaken by a Welsh police force.

Morris was arrested after the finger of suspicion wrongly pointed to Ms Power’s lover, Alison Lewis.

Former policewoman Ms Lewis and her former husband Stephen, an officer with South Wales Police, were arrested on suspicion of murder a year after the deaths.

Mr Lewis’s brother Stuart, also a police officer, was arrested on suspicion of perverting the course of justice. They were all released without charge.

A unanimous verdict by a jury at Swansea Crown Court in 2002 convicted Morris, but this ruling was overturned on appeal due to a conflict of interest by a defence solicitor.

He was convicted again at a retrial at Newport Crown Court in 2006, when he was sentenced to life imprisonment.

The Criminal Cases Review Commission had reviewed the case as recently as 2018, but at the time found no new evidence and decided not to refer it to the Court of Appeal.