WHEN Dr Caroline Muirhead met a rugged farmer on Tinder she thought she’d finally found her dream man.

But shortly after their whirlwind engagement, Alexander “Sandy” McKellar made a chilling confession that would change everything.

He told her he had killed a man and buried his body, with the help of his twin brother Robert, on a remote Scottish estate.

“He’s said, ‘he’s on the estate. You jog past him every day. He’s right beneath your feet when you shoot your clay pigeons’,” Caroline says.

That man was cyclist Tony Parsons, 63 – a cancer survivor from Clackmannanshire in Scotland who had mysteriously vanished after setting out on a 100-mile charity bike ride across the country in September 2017.

In an extraordinary twist, it would be Caroline herself who ultimately led police to his body – after secretly marking the remote burial site in the Scottish Highlands with a crushed Red Bull can.

Her evidence proved crucial in finally solving the case, helping detectives recover Tony’s remains in January 2021.

The shocking story – and the devastating toll it took – is now told by Caroline in the three-part Netflix documentary Should I Marry A Murderer?.

In 2020, Caroline, then 29, was rebuilding her life after a difficult breakup.

Working as a pathologist in Glasgow, she dealt with death daily – but hoped for something brighter in her personal life.

She joined Tinder and was instantly drawn to Sandy – a towering gamekeeper living in isolation on the sprawling Auch Estate in the Scottish Highlands.

His profile read: “6ft 4 Highlander: Lonely contractor looking for someone to keep him warm on cold nights on the farm”.

Attracted to his rugged lifestyle, Caroline struck up a conversation – and he quickly invited her to visit his remote home, around 90 minutes outside Glasgow.

Before she left, a friend unwittingly joked: “What if he turns out to be a murderer?”

The relationship moved fast.

“After our first date things moved quite fast. Because he was so far away you’d have to go for the weekend,” she says.

“I was falling for him, hook, line and sinker,” she says.

She soon became immersed in his world – spending weekends on the estate and growing close to his twin brother Robert, with whom he had grown up and worked.

“I loved him and I felt loved,” she says.

They even bonded over an unusual shared connection – death.

“We both had to deal with death on a daily basis,” she says.

“Postmortems were a large part of my job,” she says.

Sandy, who culled deer on the estate and ran a hunting agency, was comfortable around it too.

“He was very very equipped with knife skills and handling meat,” she says.

But cracks soon began to show.

The brothers drank heavily and took drugs, and Caroline, who also took drugs with them, noticed unsettling changes in Sandy’s personality.

On one occasion, Robert warned her: “My brother’s not right in the head. He’s not well,” she says.

“I was blind-sided to the red flags,” she admits.

Within months, the relationship escalated into talk of marriage – and she announced their engagement, leaving friends and family stunned.

Sandy told her: “I’ve never loved and trusted someone as much as I love and trust you.”

In November 2020, Sandy made a confession that would unravel everything though.

“He said something happened in September 2017,” Caroline says.

He described how he and Robert had been drinking after a hunting trip before driving back to the estate – over the legal limit.

“He said a big truck came with full beam and blinded him,” she says.

“In that moment he then hit a cyclist,” she says.

That cyclist was Tony Parsons.

“He said, ‘he was hit at high speed. There’s no way he was alive,’” she says.

Caroline immediately questioned him.

“I said, ‘Did you call for help?’” she says.

“He said, ‘What would we have done? If we’d called the police I’d have lost everything.

“We’d have gone to jail and lost our lives for a man that should never have been there’,” she says.

He insisted it had been an accident.

Despite her horror, Caroline says: “I believed what he was saying.

“I was so stunned I told him that I loved him, because he was crying, and that good people make mistakes,” she says.

But everything changed later that night.

She searched online and found missing person appeals for Tony Parsons, a grandfather and former navy veteran who had vanished without a trace.

The reality of what she had been told began to sink in.

Then came a second, even more disturbing request.

Sandy told her the burial site was about to be disturbed and asked for her help moving the body.

“If we can get rid of this problem then we can have a life together,” she claims he told her.

“He was asking me how long it takes to burn a human body and I was like, ‘it depends on the state of decomposition,’” she says.

“And he said ‘I poured a s*** tonne of bleach on that man, Caroline’,” she says.

That was the moment she knew she had to go to police.

She reported everything in late December 2020.

But detectives needed one crucial piece of evidence – the body.

So Caroline made a decision.

“I said, ‘Sandy, if you want me to help you with this you need to show me exactly where you buried him’,” she says.

Trusting her, he took her to the spot.

“He taps the ground and says ‘here’,” she says.

With nothing to mark the remote location, Caroline secretly crushed a Red Bull can into the ground.

It would later prove vital.

Trying to maintain normality, she continued seeing Sandy while secretly helping police.

“I was trying to almost stage normality because we were beyond not coping,” she says.

She later sent officers his live location and armed police arrested both brothers in December 2020.

“I hated myself. I felt like a rat. I felt like a liar,” she says.

But without a body, the case stalled.  The brothers were released on bail just two days later.

Caroline was left terrified they would realise she had exposed them.

She moved back in with her parents, living in fear.

But in a confusing and emotionally fraught period, she drifted back towards Sandy.

Then came a chilling new revelation.

Robert pulled her aside and told her the truth about what had really happened.

“He said ‘Caroline, I don’t know what Sandy’s told you but you have to understand when we hit that man it happened very fast. He flew over the car. We got out and when we walked towards him, he was alive’,” she says.

“I thought he’d been killed on impact. I was like, f***,” she says.

Robert went on to explain they had left Tony at the roadside.

“He said he moved him to the side of the road with the bike for them to be able to change vehicles and come back,” she says.

“And I was like, ‘Robert, you left him alone?’” she says.

They later returned, placed him in a tarpaulin, and took him back to the estate.

He was kept overnight before being buried.

“That same vehicle was used by the hunting clients the next day. Then they buried Tony Parsons once the clients left,” she says.

“In my head this wasn’t then a hit and run. This was potentially murder,” she says.

When she confronted Sandy, secretly recording him, he told her: “It was either his life or my life.”

In January 2021, forensic teams began digging at the site Caroline had marked.

Professor Dame Lorna Dawson was among those present.

“We were digging down to about 30–35cm,” she says.

“There’s red material here… it looked like the clothing Mr Parsons was wearing.

“You could see the fingerless gloves..

“And indeed, there was a ring on his wedding finger.”

As Tony’s body was recovered, she recalls: “He was lifted onto the stretcher and as he was carried out the sun came out between the clouds.

“We all stood with our heads bowed and we all said a little silent prayer,” she says.

The discovery triggered panic.

A worker mentioned the Red Bull can – and Sandy immediately realised it was Caroline who had told Police what had happened.

“You f***ing little bitch you f***ing did this,” he shouted over the phone.

He later turned up at her home.

“I honestly thought he was going to kill me,” she says.

Yet emotionally, she remained conflicted.

“We had a bond which was obviously not healthy at all but there was a bond and there was an awful lot of love,” she says.

But the truth was undeniable.

A post-mortem confirmed Tony had suffered catastrophic injuries — but had been alive after the collision.

In another recorded conversation in which he discussed Tony, Sandy told Caroline: “F*** stupid c*** shouldn’t have f***ing been there.”

In December 2021, the twins were rearrested.

They attempted to plead guilty to causing death by dangerous driving  but were instead charged with murder.

As the trial approached, Caroline – broken by what had happened and feeling unsupported by Police –  collapsed under the pressure.

“I was so ashamed of who I was and what I’d become,” she says.

She failed to appear in court on the first day as a key witness.

When proceedings resumed, the Crown accepted a reduced plea of culpable homicide.

The court heard Tony had been struck on the A82 between Bridge of Orchy and Tyndrum.

Though badly injured, he had still been alive – and no help was called.

He died within 30 minutes.

In 2023, justice was finally delivered.

Alexander “Sandy” McKellar, 31, was jailed for 12 years.

Robert, also 31, received five years and three months.

Looking back, Caroline is clear.

“He did take an innocent man’s life. So for me he is a coward and a killer,” she says.

Now rebuilding her life by the coast, she is receiving psychiatric support and trying to move forward.

“I am so lucky to be able to move forward with my life,” she says.

She has also found love again.

“I met someone new who is incredibly kind. When you love yourself you will attract healthy love,” she says.

For Tony’s family, however, the pain remains.

His widow Margaret has previously said: “When they get out of jail… I am… left with a life sentence.” The family don’t appear in the documentary.