Hector Dick, 56, was acquitted of murder in Fraser's first trial in 2003 before giving evidence against him. He told the court that his former friend admitted having his wife killed and told him that her body had been burned, her teeth had been ground up, and nothing would ever be found.
Jurors at the High Court in Edinburgh took five hours to return a majority verdict. The decision was welcomed by Mrs Fraser's parents, who have now endured two trials and two appeals, although it brings them no nearer to knowing exactly what happened to her.
Sentencing Fraser, Lord Bracadale told him: "You instigated in cold blood the premeditated murder of your wife and mother of your children, then aged 10 and five years."
The judge added: "The murder and disposal of the body must have been carried out with ruthless efficiency."
A jealous husband and aggressive womaniser, Fraser knew his wife was planning a divorce and wanted a cash settlement. He feared that she may already have had a lover, and told a friend that if he could not have her, then nobody would.
The former fruit and vegetable wholesaler had a cast iron alibi on the day she disappeared as he carried out his usual deliveries around Elgin. Fraser later made a television appeal for her to get in touch, but appeared surprisingly unperturbed, according to witnesses, and even cracked jokes about her disappearance.
The smug killer believed he had carried out the perfect crime, but in 2003 became only the third person in Scotland to be convicted in the absence of a body.
Nine years ago, he appeared in the dock alongside Mr Dick, and a third man named Glenn Lucas, who was also acquitted and has since died.
The jury in the first trial was told that the mysterious reappearance of Mrs Fraser's rings in the bathroom of the family home was the cornerstone of the case.
But the original verdict was quashed last year after the London-based Supreme Court ruled that conflicting evidence on the presence of the rings in the house was not available in 2003. It emerged that two police officers claimed they saw the rings on the day Mrs Fraser vanished.
The ruling led to a new trial in the same courtroom in which Fraser was found guilty nine years ago, and it reached the same conclusion: Fraser had "instructed, instigated and organised" the cold-blooded murder.