Jeremy Bamber's convictions for murdering five of his relatives more than 25 years ago will not be referred to the Court of Appeal, the Criminal Cases Review Commission has said.
The notorious inmate, serving a whole life term for the 1985 killings, has always protested his innocence and claims his schizophrenic sister Sheila Caffell shot her family before turning the gun on herself in a remote Essex farmhouse.
But after reviewing material provided by Bamber's legal team, the Criminal Cases Review Commission (CCRC) said it had reached "a provisional decision not to refer his murder convictions to the Court of Appeal".
The CCRC said it had sent Bamber's legal team an 89-page document "setting out in detail the Commission's analysis of the case and the reasons for the provisional decision".
"As is usual with commission cases reaching this stage, Mr Bamber and his team have been invited to respond to the commission's case analysis and the reasons for its provisional decision," a spokesman said.
"Given the lengthy and highly complex nature of the case, we have given Mr Bamber and his team three months in which to respond to our provisional decision (usually the period for a case of this type is 40 working days).
"The commission will then consider whatever representations it receives from Mr Bamber and his team before making a final decision on whether or nor to refer the case for a fresh appeal hearing."
Last year, it emerged that photographs which were used as prosecution evidence against Bamber were to be reviewed after an expert claimed there were discrepancies on crime scene pictures.
Bamber's defence team claimed police photos of the murder scene could help him overturn his convictions
They said the new images cast doubt on part of the prosecution's case and showed the gun seemingly resting in different positions on Ms Caffell's body and around the bedroom.
They also claimed that because the trial jury heard he had re-staged the crime scene, the photos show that he was not given a fair trial or at least raise questions about inconsistencies in the evidence.
The rifle was above and below Ms Caffell's neckline in different close-up images.
And in wide shots of the room, the gun appeared propped up against a window and was then missing in another.
Bamber, who is being held in Full Sutton prison in York, has been behind bars for 24 years for shooting his wealthy adopted parents, June and Neville, his sister Ms Caffell and her six-year-old twin sons Daniel and Nicholas at their farmhouse in Tolleshunt D'Arcy, Essex, on August 7, 1985.
The 50-year-old was given a whole life tariff after being convicted of the murders in October 1986.
In 2009, Bamber lost a Court of Appeal challenge against the order that he must die behind bars. He has twice lost appeals against conviction.
Essex Police said it had co-operated with the CCRC and "has no further comment to make at this time".Reuse content