No information has been provided by two potential new witnesses that undermines the conviction of a man for the notorius murder of a family more than 20 years ago, police said.
Mandy Power, 34, her bed-ridden mother Doris Dawson, 80, and her daughters Katie, 10, and Emily, eight, were found dead by firefighters at their home in Clydach, near Swansea, in June 1999.
All four had been bludgeoned to death with a pole before their house was set on fire.
Former builder David Morris was jailed for a minimum of 32 years having been convicted for a second time of their murders in 2006.
An earlier conviction was quashed by the Court of Appeal when a second trial was ordered.
Morris has long maintained his innocence, and last year a programme by BBC Wales Investigates questioned the safety of the conviction.
It featured interviews with two potential witnesses – one who said he had never spoken to police and the other who said he contacted police to report what he had seen but nobody ever called him back.
South Wales Police said it had spoken to the two men and sought advice from the Crown Prosecution Service, who said no information had been provided that undermined Morris’s conviction.
“In January 2021, South Wales Police announced an investigative assessment of specific areas referred to by legal representatives of David Morris,” a force spokesman said.
“This work has also included following up potential new witnesses identified in a BBC Wales Investigates programme on the case.
“As part of this work, detectives have spoken to both witnesses and the Crown Prosecution Service has advised that no information has been provided which undermines the conviction of David Morris.
“The investigative assessment, which is being overseen by a senior investigating officer, a deputy and a forensic investigator from Devon and Cornwall Police, is now moving to consider the forensic issues that were challenged within the BBC documentary.
“While this work continues, our thoughts remain with the families and those affected by this case and acknowledge the significant impact it has on them.”
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.
The Clydach inquiry was the largest and most complex murder investigation ever undertaken by a Welsh police force.