Not proven: the Ardlamont mystery

What happened

Cecil Hambrough, a young man of twenty, died of a gunshot wound on the Ardlamont estate in Argyll, on Scotland's west coast, on 10 August 1893. He was out that day with his tutor, Alfred John Monson, a man engaged to prepare him for a military career. A shot was fired. Hambrough was found dead of a head wound, and Monson raised the alarm.

Monson had recently taken out substantial life insurance on Hambrough, with his own family named among the beneficiaries. He was also, by most accounts of his finances at the time, in serious debt. Those two facts, sitting next to each other, are the reason this stopped being a shooting accident and became a criminal trial.

Monson was arrested and charged with murder. The case went to the High Court of Justiciary in Edinburgh that December, under the name HM Advocate v Monson, and became one of the most closely watched criminal trials Scotland had seen.

The evidence

There was no independent witness to the moment the gun went off. The case turned instead on the wound itself, and on how close the barrel had been to Hambrough's head when it fired. A close-range shot fit an accident. A shot from further off fit a deliberate act. The two sides of the courtroom could not agree which one the body showed.

For the prosecution, the Edinburgh surgeon Joseph Bell, later the real-life model for Sherlock Holmes, examined the evidence and told the jury he believed Monson had killed Hambrough. For the defence, Professor Matthew Hay gave evidence that directly contradicted him. Two credentialled experts, looking at the same wound, reached opposite conclusions in open court, and the jury was left to decide which expert to believe rather than what had actually happened.

The insurance policies were laid out for the jury as motive. Monson's advocate worked to unpick the medical case rather than the financial one, and it was the medical uncertainty that ultimately did the work.

How it's been argued over, then and since

After 73 minutes of deliberation, the jury returned Scotland's third verdict: not proven. It is not the same as not guilty. English law and most of the world only offer two answers, guilty or not guilty, and not guilty means the state failed to prove its case, full stop. Scots law has a third option that says something narrower and stranger: the jury was not convinced enough to convict, but it is not saying it believes the accused is innocent either. It is a formal acquittal that answers the legal question while pointedly declining to answer the human one. Monson walked free. He was never tried again, and under the law he did not need to be.

The public did not treat the verdict as an answer. Madame Tussauds put a waxwork of Monson on display in a setting that strongly implied he was a murderer, and he sued for libel. He won the case and was awarded one farthing, the smallest coin in circulation, a verdict so close to the trial's own that it has been read ever since as the public's real opinion, delivered in cash rather than words. The not proven verdict has stayed at the centre of Scottish debate over whether the option should exist at all, cited for exactly this reason: it lets a jury step back from a decision that guilty or not guilty would have forced them to make.

Murder Mystery Party's case, Not Proven, puts your table on the Ardlamont estate on the day of the shooting, working through the same disputed wound, the same insurance policy and the same two experts who could not agree, and asks your guests to reach a verdict an Edinburgh jury spent 73 minutes deliberately not reaching.