Lee and Robert Firkins claimed a trial witness lacked credibility
Two Somerset men jailed for life for killing a Cornish couple have lost their appeal against their convictions.
Brothers Robert and Lee Firkins, aged 35 and 33, from Weston-Super-Mare, were found guilty in February 2006 of the murders of Graham and Carole Fisher.
The couple had been beaten and shot in their Wadebridge home and the brothers were jailed for life.
Their attempt to overturn the convictions was rejected by three judges at London's Court of Appeal.
The brothers said they were elsewhere in Cornwall when the killings took place on Bonfire Night in 2003.
The four-day appeal hearing hinged on whether a witness who testified against the brothers at their trial lacked "credibility".
The three Appeal Court judges declined a request to call "witness X" to testify about his reasons for writing a letter in December 2006 to a newspaper reporter, which defence lawyers said cast doubt over his testimony at their trial.
The witness, who is on a protection scheme and cannot be identified, had shared a cell with Robert Firkins.
He told the trial at Exeter Crown Court that his cellmate had confessed to killing 60-year-old Graham and 53-year-old Carole on 5 November at their home next to the petrol station they owned.
However, the Appeal Court judges refused to hear fresh evidence from witness X and dismissed the brothers' appeal.
Carol and Graham Fisher were killed in their home
Delivering judgment on the appeal, Lord Justice Hughes said witness X was a recidivist criminal with a drug habit.
"He was demonstrated to have lied at a number of points in his evidence when these and other aspects of his history were put to him," he said.
But, he added, there was a wealth of other evidence which supported the prosecution case that the brothers were the killers.
That included their previous convictions for robbery, their "extreme violence" and their ownership of sawn-off shotguns.
Their "improbable" claim that they were only in the area having driven almost 300 miles to buy a small amount of cannabis also supported the prosecution case against the brothers.
Robert Firkins had also been "distressed and tearful" in a call to his girlfriend and a witness had described hearing him talking about "the Wadebridge thing" to others, he added.
"We are quite satisfied that this case did not depend wholly upon witness X," the judge said.
"On the contrary, the other evidence in the case was potentially highly significant support."