The unsolved murder of Scots soldier Sandy Drummond, which to this day remains shrouded in mystery, is to be brought to light once again and examined by experts.
The former soldier, whose full name was Alexander Drummond, was only 33 when his body was discovered in an open field near his Borehills home in Fife back in 1991. His death has left a series of questions which remain unanswered more than 30 years later - ones which Scots criminologist David Wilson hopes to answer.
In the latest episode of the BBC documentary series "David Wilson's Crime Files: Cold Cases", which airs tonight, the crime specialist explores Scottish deaths that are "clouded in mystery."
Speaking with crime writer Douglas Skelton, who is deeply familiar with the case, he attempts to uncover a possible motive for the puzzling crime - with Skelton suggesting he may have been harbouring a dark "sexual" secret.
"Drummond's mother said he was a very happy person, very pleasant person. Like her he was a person of faith, but he could be shy", said Douglas.
"He wasn't a loner she said, but he could just be shy - once he got to know you he was as open as anybody. But he changed and it was the change that's so curious about this.
"He changed from this happy person - this person that was interested in nature, in wildlife, in astronomy. And he became, 'sad' I think is the only word to use."
So, who was Sandy Drummond and what may have caused his transformation in the months leading up to his death?
Who was Sandy Drummond?
David Wilson introduces Sandy Drummond as "a kind, gentle, intelligent man, who largely kept himself to himself".
After serving in Northern Ireland with the Black Watch infantry, Sandy moved into a cottage with his brother James Forsyth and worked at the guard bridge paper mill for seven years. His mother Effie said he was a loving son and a "carefree countryman", until the months leading up to his death - when she noticed a change and he became troubled.
Sandy requested a position transfer at work and never revealed the reason behind his sudden shift in mood. About a week before his death, he unexpectedly quit his job without giving notice. It was after this he told his brother that he was thinking about taking a trip on his motorcycle for a break.
That same evening, Sandy visited his mother, giving her a kiss before driving away on his bike. It was the last time Effie would see her son alive. On the morning of June 24, witnesses say Sandy rushed out of his house holding a blue sports bag, after his brother James left for work.
CCTV footage placed Sandy at an ATM later that day, withdrawing nearly all of his savings. He had previously taken out cash from another account the day before, making his total sum £800.
That night at 8pm, Sandy's body was found on a farm track just a few hundred yards away from his home by an elderly walker.
The murder of Sandy Drummond
Sandy was lying face down with his hands embracing his stomach. It was this position that led authorities to believe his death had occurred naturally. But Wilson says that "all was not as it seemed".
A post-mortem determined that Sandy had suffered a "jujitsu style" hit to his neck, which extensively damaged its muscles, resulting in asphyxiation and like strangling, caused him to suffocate. The enquiry quickly transformed into a murder investigation.
There are a number of factors which make Sandy's death all the more mysterious. The afternoon that he died, Wilson reports that a man with a bloody, bandaged hand was seen getting on a bus near Sandy's home.
Witnesses reported seeing a red or orange Morris Marina car parked at Sandy's cottage several times - with some seeing it on the day of his death.
The blue sports bag Sandy was seen with was missing, but oddly enough, all the money he withdrew was found back at his home. This prompted investigators to rule out robbery as a motive.
The murder of Sandy Drummond is one that left investigators with more questions than answers. The blue sports bag, bandaged man and car are pieces of a puzzle officials still can not piece together.
But Douglas Skelton suspects that Sandy's death was all to hide a secret, one he could not bring himself to admit to his mother.
Skelton spoke to Effie on several occasions after his death and she believe it is his sudden transformation from a pleasant but shy person into a "sad" withdrawn man that ultimately led to her son's demise.
Skelton recalled a story Effie told him, when her son broke down in tears, while they sat beside a fire. She begged Sandy to open up on what was bothering him, but he said he could not tell his mother as "it's too filthy". Sadly, Effie would pass away in 1995 without knowing who killed her son.
Skelton continued: "There was something in Sandy's life that he was not proud of. That he was possibly ashamed of but he couldn't tell anybody.
"We have to make the leap that it's sexual, because the use of the word 'filthy' automatically suggests that it's something sexual. Obviously there was something there and it seemed to be focused somehow on his place of employment.
"Because he became increasingly disenchanted with being there and even moved job within it at one point to try to get away from something. And eventually, he walked out and didn't give any notice really and that was about a week before he died."
Skelton said investigators at the time worked tirelessly to uncover Sandy's dark secret, but found nothing, with one even saying "he was as clean as the 'Ark Angel Gabriel'".
Skelton highlights that Sandy's death was not a violent one. He said that while he was left with bruises and contusions, it was a seemingly quick painless death, compared to a more gruesome form like stabbing or shooting.
But when Wilson asks if he thinks this crime of "secrets and silences" can ever be solved, Skelton admits that he is not optimistic. He concluded: "I don't think so. I think if there had been that one bit of evidence that was needed it, would've come in by now.
"I can't see it happening unless somebody confesses or somebody finds something solid."
David Wilson's Crime Files: Cold Cases airs on BBC Scotland on Tuesday October 18 at 10pm.
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