A romantic journey that began with promise between a forensic pathologist and a farmer took an unexpected turn, revealing a link to one of Scotland’s most enigmatic disappearances.
Dr. Caroline Muirhead and Alexander “Sandy” McKellar’s relationship, now the subject of Netflix’s gripping docuseries Should I Marry a Murderer?, began on the dating app Tinder in 2020. Their connection was immediate and intense, leading to a swift engagement. However, their happiness was shattered when Sandy confessed a shocking secret: he and his twin brother, Robert McKellar, were involved in the death of a man whose vanishing had puzzled authorities for years.
Caroline faced a heart-wrenching dilemma—should she protect the man she loved or report him to the police, thrusting herself into the midst of a criminal investigation?
Here’s what you need to know about Caroline Muirhead and the McKellar twins.
Sandy McKellar and Robert McKellar’s Car Crash That Killed Tony Parsons
When Caroline and Sandy first met, Caroline was recovering from a recent breakup. Concerned friends worried that the couple was moving too quickly.
“I phoned my friend Carla…she was like, ‘What if he turns out to be a murderer?’” Caroline recalled in the documentary series. “I was like, ‘Come on, get a grip, that’s not going to happen.’”
The couple spent all their time at Scotland’s Auch Estate, where Sandy farmed and hunted in the remote Scottish Highlands. Meanwhile, Caroline—a pathologist—said Sandy, a hunter, seemed relieved to find a partner who understood working with death on a daily basis.
“Sandy was very interested in my work,” Caroline said in the documentary. “We both had to deal with death on a daily basis.”
But according to Caroline, Sandy soon made a confession: Three years ago, while driving drunk with his twin brother Robert as passenger, he accidentally hit cyclist Tony Parsons, a Navy vet and cancer survivor.
Caroline said in the documentary that according to Sandy, he and Robert stopped to check on the man but there was no chance of survival. They argued over whether to call the police, but fearing arrest, they buried his body and moved on with their lives.
The case had long gone cold, though Tony’s family still had no answers.
While Caroline was tormented by Sandy’s confession, she ultimately chose to stand by her fiancé.
Then came the question that changed everything: Could she help move the body?
Caroline Muirhead’s Role in Sandy McKellar and Robert McKellar’s Murder Case
Sandy told Caroline that the estate owner planned to build housing on the land where Tony was buried. Relying on her expertise in autopsies, he asked how long it would take to burn a human body and if she could help move it elsewhere.
“You’re thinking to yourself, ‘Am I being used for my skill set?’” said Caroline. “I had ‘pathologist’ on my Tinder profile—did he choose me specifically because he wanted someone to help him with this?”
Caroline knew she needed to end the relationship, but carefully. With the support of her parents, she contacted the authorities and began secretly helping the investigation.
She returned to Auch Estate under the guise of being with Sandy, and during a hunting excursion, he brought her to Tony’s burial site, where she secretly left an empty Red Bull can as a marker, then led investigators to the brothers.
However, when arrested and questioned by police, Sandy and Robert refused to answer and were later released due to lack of evidence.
Meanwhile, Caroline secretly recorded her conversations with Sandy in the hopes of drawing out a confession.
“You’re living with killers, sleeping alongside killers, you’re having dinner alongside killers,” Caroline said in the documentary. “Killers who think you’re on their side.”
Robert then dropped a bombshell on Caroline.
According to Caroline, Robert said that Tony didn’t die right after the crash. Instead, he was alive while the brothers hid him on the side of the road, then drove home, changed clothes and returned to the scene, where they found Tony dying.
In Caroline’s eyes, the crime had evolved from a spontaneous bad decision to cold-blooded murder. Still, Caroline wrestled with her feelings for Sandy and continued their relationship.
Then, in Dec 2021, months after Tony’s frozen body was discovered on Auch Estate, Sandy and Robert were charged with murder.
Caroline was later summoned to appear as a witness in the July 2023 trial.
However, Caroline didn’t show up for court, explaining in the documentary that she panicked and drove to was driven to the Highlands in the hopes of finding more evidence and was later arrested for evading court.
Where are Sandy and Robert McKellar Now?
Sandy ultimately pleaded guilty to culpable homicide while Robert admitted to concealing and burying Tony’s body. In August 2023, Sandy was sentenced to 12 years in prison while Robert received a sentence of five years and three months.
In court, Sandy’s attorney read a statement on his behalf to the judge.
“He accepts that while catastrophically injured, Mr. Parsons was alive at the time,” according to the statement. “The only explanation which he offers is simply fear and panic. Using his words, he says he was too much of a coward to come clean. When he met Caroline, and she went to the police, he fully accepts that ultimately, she made the right decision in doing so.”
Where Is Caroline Muirhead Now?
Today, Caroline has no regrets about bringing the case to justice.
“This is what happened to me, it’s my story,” she said. “I just hope other people can learn from it so they don’t make the same mistakes I did.”
Caroline has now moved to the coast of Scotland said in the documentary that she is seeing a psychiatrist to, as she said, “tackle a lot of the insecurities that led me to be in the vulnerable relationship to begin with.”
She has also entered a new and better relationship.
“When you love yourself,” said Caroline, “you will attract healthy love.”