Mass murderer Jeremy Bamber has launched a fresh bid for freedom based on newly discovered photographs.
The images - recently submitted to the Criminal Cases Review Commission - could potentially undermine his conviction for killing five family members at White House Farm in Essex in 1985.
Bamber's legal team have said that the photographic evidence indicates that the police possessed two different silencers during the original investigation with the second never being disclosed to the defence, The Mirror reports.
Bamber, 64, was found guilty of murdering his adoptive parents Nevill and June, both then 61, his adoptive sister Sheila Caffell, then 26, and her then six-year-old twin boys Daniel and Nicholas at White House Farm in Tolleshunt D'Arcy, Essex, 40 years ago.
Bamber, 64, was found guilty of a mass murder at a family home in Essex 40 years ago
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The new photographic evidence includes three key images that Bamber's team say could prove the existence of more than one silencer.
One image from October 1985 shows a silencer with material taped around it, while footage from October 1986 displays DC Christopher Whiddon presenting a silencer without tape to the media.
A third photograph from 1999 - used in DNA testing before Bamber's 2002 appeal - shows yellow tape embedded in the silencer's surface in the same location as the 1985 image.
Bamber's lawyers have argued that these differences in tape placement prove two separate silencers were involved in the investigation.
Mark Newby, Bamber's lawyer, said: "The whole tenet of the case run by the Crown in the original trial was that there was one silencer.
"The whole basis of the case was to link it to one and to argue the only possible explanation for that was that Jeremy had staged the scene, which was then linked to blood on that one silencer.
"It's all interlinked and so if there were two it undermines potentially all the evidence the Crown linked to this silencer. So it's really important if there were two."
The silencer evidence played a significant role at the original trial
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Bamber, 64, was found guilty of murdering five people, including two children, forty years ago
PA
Former police scenes of crime officer Jacqueline Chapman, who worked as a forensic investigator for 21 years, said it would have been "impossible" to remove and reattach tape after the silencer underwent fingerprint testing.
Essex Police has strongly defended the original conviction, saying that Bamber "needlessly, tragically and callously" killed five people - including two children - in their own home.
A spokesman for the force noted that several appeals and reviews by the Court of Appeal and Criminal Cases Review Commission have consistently found Bamber to be responsible.
Essex Police said it has continued to comply with all legal requirements in the case and will continue to assist the CCRC as required.
The wider submission includes 12 pieces of newspaper and broadcast evidence from September 1985, including a Daily Mirror front page, which reported police statements about a silencer being retrieved on the day of the killings.
In a recent letter to the Mirror, Bamber said: "From day one I've stuck to my evidence that this case features two sound moderators. The photos of two sound moderators and news articles can not be dismissed."