How a Red Bull can helped solve mystery of missing cyclist

It was two months into their relationship when Dr Caroline Muirhead's new boyfriend confessed he had killed a man and left him in a shallow grave.

Alexander McKellar offered to take her to the spot where the body was buried – and her quick thinking was crucial in cracking a case which had baffled police for three years.

Caroline secretly dropped a can of Red Bull at the spot, in a remote estate in Argyll, then called police to tell them about the location.

The shallow grave contained the body of Tony Parsons, who had gone missing on a charity cycle ride three years earlier.

Tony's son Mike said that without Caroline's intervention, it was unlikely that his body would ever have been found – and expressed the family's gratitude for what she had done.

The case is the subject of a new two-part documentary which reveals the twists and turns of the police investigation and the Parsons family's long wait for justice.

Mike Parsons told BBC Scotland News that his dad was the kind of man who was always determined to complete any challenge he set himself.

Tony had previously been treated for prostate cancer and wanted to give something back.

So he planned a 104-mile charity cycle from Fort William to his home in Tillicoultry, setting off on Friday 29 September 2017 and cycling through the night.

Mike said his family started to become concerned when Tony had not contacted them by Saturday night.

"I actually texted him myself, with what is my dad and myself's sense of humour, a simple text: 'Are you still alive?'

"Looking back now, it's not nice to know that was the very last thing I texted to him, knowing at this point he would have been passed away."

Tony was subsequently reported missing, sparking a major search operation.

Police knew he passed through Glencoe Village at about 18:00 on Friday before going on to the Bridge of Orchy Hotel in Argyll.

The last known sighting of him was at the hotel at 23:30 that night, before he headed south on the A82 in the direction of Tyndrum.

As the days progressed, former police officer Mike and his family grew increasingly concerned about Tony.

"I knew the timescales that would be involved," he said.

"The longer the days went on, I knew in my head that the chances of him being found alive would be pretty slim.

"But I basically had to convince my mum there was still a chance, and lying to somebody like that is not easy."

Despite numerous public appeals including an appearance by Mike on Crimewatch, it seemed that Tony Parsons had vanished into thin air.

Then, in late 2020, police received a phone call that would change everything.

The female caller was distressed.

She said she had information about a crime that had been committed three years earlier at Bridge of Orchy.

It concerned a hit and run, the concealment of a body, and lying to police.

She said the victim's name was Tony Parsons.

The caller was Dr Caroline Muirhead, the girlfriend of Alexander McKellar. Known as Sandy, he worked on a nearby estate with his twin brother Robert.

Police had spoken to the brothers after an anonymous letter in August 2018 said they were in the Bridge of Orchy Hotel the night Tony Parsons had vanished, but no further action was taken.

In June 2020, they were again questioned about Tony and confirmed being in the hotel with a hunting party that night. However, they said they had not seen the cyclist.

In November 2020, Caroline Muirhead and Alexander McKellar had been together for two months.

She asked her boyfriend if there was anything in his past which may affect their future together.

He told her he had hit Tony as he drove home from the hotel with his brother, but did not seek medical assistance.

It was later revealed that Tony's injuries were so bad that he would only have survived for 20 or 30 minutes without help - but it was unlikely that he had died instantly.

The twins left the area and came back to the site in another car before taking Tony's body to the Auch Estate, where they buried him.

Mike Parsons said: "What they did was inhumane and you wouldn't do that to animals.

"They killed him by not seeking any medical treatment."

After confessing to his girlfriend, Alexander McKellar led her to the shallow grave where Tony's body had been buried.

Caroline secretly dropped a Red Bull can as a marker for the spot, before later calling police.

Mike Parsons said she had shown "remarkable foresight."

"Being brutally honest, I'm not so sure if I was in the same situation I would have done and thought the same way.

"From my perspective, I have nothing but massive amounts of gratitude for that, because had she not done that and put herself into these positions, then we would never have found my dad's body."

Tony's body was recovered from the grave in January 2021 after a two-day operation by specialist officers.

He was found to have suffered "catastrophic" rib, pelvic and spine fractures following the collision.

Tony's funeral was held at Stirling Crematorium in April 2021.

The brothers were arrested and questioned twice by police, but were initially uncooperative, giving "no comment" interviews.

With the evidence against the twins mounting, police eventually charged the pair with murder.

In July 2023, shortly before their trial was due to begin at the High Court in Glasgow, Sandy McKellar admitted the reduced charge of culpable homicide.

His brother had his not guilty plea to murder accepted, but the pair both admitted attempting to defeat the ends of justice by covering up the crime.

Sandy McKellar was sentenced to 12 years in jail, while his brother was jailed for five years and three months.

Mike Parsons said that no sentence would ever be enough.

"They have left my mum without a husband and us without a father."

Mike said he would like his dad was remembered for the good he did in his life, rather than the circumstances of his death.

"For me, he was a grumpy old dad who you had your run-ins with every now and then," he says, smiling.

"But, I'd like people to remember him as just the guy who wanted to help everybody."