A COLD case investigator caught a pair of killer twins who buried a cyclist in the woods after he unravelled their sick ruse.
Tony Parsons had vanished without a trace during a solo charity bike ride from Fort William to his home in Tillicoutry in September 2017.
He had stopped for a pint at the Bridge of Orchy hotel before his life sadly came to an end.
Tony was struck by on the A82.
But Sandy callously abandoned his stricken victim before teaming up with twin brother Robert to bury Tony's body “like an animal” in a remote peat bog in September 2017.
For three years, the case had run cold, with the twins having lived with their evil secret for just over three years.
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But Sandy later told his lover Dr Caroline Muirhead, 32, he had and evaded justice for over three years with the help of his brother.
Caroline, who had met Sandy on Tinder, was shocked to hear of the devastating confession in November 2020 as they spoke about plans to get married.
But it was Professor David Wilson who made the key connection which turned the tide in the unsolvable case.
The top criminologist, who presented ITV show 'In the Footsteps of Killers' exclusively revealed to The Sun Online how he helped snare the evil twins.
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He said: "Nobody knew anything about this or what had occurred.
"The reason why it became hot case again that led to their arrest and conviction is that the old girlfriend of one of those twins came forward.
"I happened to be giving an interview on BBC Radio Scotland and said we'll never know what happened with Tony."
But shortly after, Caroline, got in contact with Professor Wilson having heard the radio interview.
He continued: "We'll never understand why she felt able to discuss this.
"She heard me give the interview on Radio Scotland, contacted my agent and then she phoned me.
"And until she called, we didn't know anything about the case."
This proved to be the catalyst for a full investigation in which the the twins were snared.
But Professor Wilson said that the sick killer had actually looked for something in particular while on the dating app.
He added: "Caroline said she had got sick and tired of meeting guys who had worked in the same profession as she did.
"So she met this guy, one of the twins who was a hunter in the north of Scotland.
"He was just so out of what was her usual dating circle that she fell head over heels in love.
"Here's when it becomes really odd. And I said: 'Caroline - did you put your profession on the dating app?'
"And she went: Yes, I put I was a forensic pathologist.'
"He groomed her because where he buried the body that land had just been sold to make way for a hotel that was going to be built.
"Sandy had groomed her into a relationship so that she would give him better advice about how to dispose of the body."
Dr Muirhead then helped detectives build a case against her ex by going undercover and living with him to gather evidence.
Caroline, of Glasgow, in a Highland estate using a red bull can she left behind to mark the spot before contacting cops.
High Court was also told the ex-Navy officer's body may never have been found without Caroline's revelation due to the remote location of the Auch Estate near Bridge of Orchy in 2017.
However, Caroline could now launch legal action against Police Scotland over claims she felt "coerced" into spying on her ex after she alerted them to the grave site.
Caroline told the how the nine-month undercover ordeal left her close to breakdown with her mental health shattered and unable to work.
She said: “From the word go the police they were saying if I didn’t cooperate with them I could end up in trouble myself.
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“I put so much trust in them and they promised anonymity, support, yet the minute you give them what they want you’re hung out to dry.
“They suggested from the start that I could also end up in trouble with assisting a criminal, wasting time, aiding and abetting.”