True crime fans, clear your schedules. Netflix’s latest documentary Should I Marry a Murderer? has just dropped, and it’s arguably one of the most gripping and harrowing stories featured on the streaming service in years.
The three-part docuseries follows the unimaginable dilemma of Dr Caroline Muirhead, a pathologist who thought she’d found her happily ever after on a dating app, only to later discover her fiancé was hiding a truly horrific secret.
If you’ve already binged the trailer or simply need a debrief before diving into the episodes, here is everything you need to know about Dr Caroline Muirhead, the tragic case of Tony Parsons, and where the brave fiancée-turned-witness is today.
Who is Dr Caroline Muirhead?
Dr Caroline Muirhead is a Scottish forensic pathologist whose life changed forever after a fateful swipe right. In September 2020, she matched with Highland gamekeeper, Alexander 'Sandy' McKellar on a dating app. After a whirlwind romance, the pair fell deeply in love and were soon engaged. Muirhead described feeling "accepted, wanted, seen" by her new partner, blissfully unaware of his dark past.
But a couple of months into their relationship, Muirhead asked a question that would blow her world wide open: was there anything in his past that could affect their future? It was then that McKellar dropped a devastating bombshell, confessing to his involvement in a fatal, covered-up hit-and-run.
What did her fiancé Alexander McKellar do?
In September 2017, Alexander McKellar and his twin brother Robert were driving along the A82 in Argyll, Scotland, after drinking at a local hotel with a shooting party. Their vehicle struck and killed 63-year-old cyclist Tony Parsons. Tragically, Parsons – who was a retired Royal Navy officer, grandfather, and cancer survivor – was cycling a 100-mile route in aid of a prostate cancer charity at the time.
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Instead of calling for help, the McKellar brothers went to horrific lengths to hide what they’d done. They swapped vehicles, returned to collect Parsons and his bike, and buried his body in a bog used for dead animals on the 9,000-acre Auch Estate where they lived and worked. For three years, Parsons' family had no idea what had happened to him.
How did Caroline Muirhead catch him?
After the confession, Muirhead was faced with the ultimate unthinkable dilemma: stay loyal to the man she loved, or risk everything to expose the truth. Choosing to do the right thing for Parsons and his family over her future marriage, Muirhead went undercover to gain more information from McKellar.
She bravely coaxed McKellar into taking her to the makeshift grave, where she secretly marked the exact spot by stamping a Red Bull can into the ground. She then tipped off Police Scotland, working as a covert witness over several gruelling months to gather evidence that led to the brothers’ arrest in December 2020.
In August 2023, Alexander McKellar was sentenced to 12 years in prison for culpable homicide and attempting to pervert the course of justice. His brother, Robert, received a five-year sentence.
Where is Dr Caroline Muirhead now?
After successfully bringing her former fiancé to justice, Dr Caroline Muirhead naturally stayed out of the public eye to process the immense trauma of the ordeal.
However, she is now ready to reclaim her narrative. In the new Netflix series, Muirhead tells her side of the story for the very first time. She shares deeply personal mobile phone footage, her own anguished reflections, and details the profound mental toll of living a double life to expose a killer.
As she asks in the trailer: "To remain in love, you have to keep this secret that you know is gonna destroy you. But if you reveal it, then you destroy everything. I mean, what would you do?"
When is Should I Marry a Murderer on Netflix?
Should I Marry a Murderer? was released globally on Netflix on 29 April 2026.
