The True Story Behind Netflix’s Should I Marry a Murderer? Crime Documentary

Have you ever wondered between a battle of romance and justice, what would win? Can someone sacrifice their chance at finding love because they need to be brought to justice? Giving viewers a glimpse into their crucial question is Netflix’s true-crime documentary, Should I Marry a Murderer?, set to be released on April 29, 2026. 

The series explores a real case centered around a woman who discovers her fiancé’s dark secret and is subsequently faced with a terrible dilemma. She has to choose between protecting the one she loves and bringing justice to the mourning family. The documentary explores the psychological conflict between love and morality, a question that never has an easy answer.

Through firsthand accounts, particularly from forensic pathologist Caroline Muirhead, the series reconstructs a disturbing case involving Alexander “Sandy” McKellar and the death of cyclist Tony Parsons.

What Happens in Should I Marry a Murderer?

The documentary follows Caroline Muirhead, a young forensic pathologist who meets Alexander McKellar on a dating app in 2020. What can only be defined as a whirlwind romance, the couple quickly catches feelings for each other and even gets engaged. However, their dreams of a perfect life come crashing down when McKellar confesses to a crime he committed years earlier.

He reveals that in 2017, he hit a cyclist, Tony Parsons, while driving under the influence in the Scottish Highlands. His twin brother, Robert, was also in the car with him. Instead of reporting the accident or seeking medical help, McKellar and Robert left the victim at the roadside and later concealed the body. When Caroline asked McKellar if he wanted to share anything before they got married, a confession to a murder must have been the last thing on her mind.

The series documents how Caroline processes this information and ultimately decides to cooperate with the authorities. Rather than immediately exposing him, she carefully gathers evidence while maintaining the relationship. The documentary uses interviews, reconstructions, and real investigative details to show how she brought the grieving Parsons family a sense of justice. It certainly must have been very difficult for Caroline to come to terms with this decision and then live with the consequences.

How Did Alexander McKellar Get Arrested?

Alexander McKellar was arrested, all thanks to Caroline Muirhead’s quick thinking and brave investigation. After his confession, McKellar shows Caroline where the body is buried, and she therefore alerts the police by marking the location of the grave with a Red Bull can.

This critical detail eventually led to McKellar’s arrest, with the authorities being able to locate the remains of Tony Parsons in early 2021. This discovery became the breakthrough the case needed. McKellar and his brother were arrested in December 2020, although the process involved multiple stages, including initial questioning, release on bail, and re-arrest after further evidence surfaced.

Caroline put herself in danger by remaining in close contact with McKellar and continuing the relationship while secretly assisting the police, fully aware of the potential consequences if he discovered the truth. Her courage eventually brought the McKellar twins to justice.

Where Is Alexander McKellar Today?

Following a lengthy investigation and legal proceedings, Alexander McKellar was convicted in 2023. Although initially charged with murder, the case concluded with a conviction for culpable homicide and attempting to defeat the ends of justice. He was sentenced to 12 years in prison by the High Court of Glasgow. (via BBC)

His sentence was reportedly backdated to his 2020 arrest, meaning he has several years left to serve, with the possibility of parole in the future, subject to legal conditions. His twin brother Robert, who helped conceal the crime, received a shorter sentence of just over five years and has likely been released. 

Today, McKellar remains in prison in Scotland. It’s quite intriguing to see how the documentary features all the details that helped build the case over time, and how the Parsons family found answers to many questions they must have had for a long time.

Understandably, Caroline has been rebuilding her life after the ordeal. Nobody can imagine how she has managed to deal with the entire situation, let alone move on with her life after it all wrapped up. Her story ultimately becomes one of resilience, even as it raises uncomfortable questions about trust and human behavior.

Should I Marry a Murderer? is not just a clickbait question but a very real dilemma that Caroline faced when she heard the confession. Her seemingly ordinary life got turned upside down, and she had to make a decision that impacted many people. It’s a haunting reminder that sometimes, the most dangerous secrets are the ones hidden in plain sight. 

Should I Marry a Murderer? will be streaming on Netflix on April 29, 2026.