Bangladeshi national Shamsuddin Mahmood, 26, was shot point-blank in the head by a masked gunman in front of diners at Mumutaz Indian Tandoori Restaurant in Kirkwall on 2 June 1994.
Michael Ross, who was just 15 at the time of the murder, was found guilty of the crime in 2008 and sentenced to a minimum of 25 years in prison.
Ross, who joined the British Army and rose to the rank of sergeant in the Black Watch, attempted to flee the High Court in Glasgow when convicted but was captured and jailed.
Since then, he has continued to maintain his innocence and has attempted to escape prison multiple times.
A previous bid by Ross to have his conviction re-examined by the Scottish Criminal Cases Review Commission (SCCRC) was rejected in 2014.
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On Monday, the SCCRC told Sky News it was restricted by law in regards to the information it could disclose about the cases it reviews.
However, it confirmed it had received a further application from Ross which had been accepted for a review.
Following the re-examination, the case could ultimately be referred back to the courts.
