The Poisonous Solicitor: The True Story of a 1920s Murder Mystery by Stephen Bates

When Katharine Armstrong died, quietly in her bed, on a Tuesday morning in February 1921, the circumstances surrounding her death were so ordinary that the very idea that a book might be written about it a century later would have seemed absurd.

Yet over the years her demise would come to inspire a good deal more than just this meticulously researched new investigation by Stephen Bates. What happened after the 48-year-old passed away in sleepy Hay-on-Wye fueled the creative minds of some of the greatest detective novelists of the 20th century — Agatha Christie, Dorothy L Sayers and Georgette Heyer — as they forged the Golden Age of crime writing. Centering on her husband, Major Herbert Armstrong, who, the year after Katharine died, was sensationally found guilty of her murder and hanged, the tale delivers many of the themes we still associate with classic detective fiction.

Although the case took up endless newspaper column inches during the early 1920s, the story of upstanding country solicitor Major Armstrong and his pocket supply of arsenic has largely been forgotten in recent years, with just two books published in the past five decades — Exhumation of a Murder by Robin Odell in 1975 and Martin Beale’s Dead Not Buried in 1995. The whole mysterious affair is therefore ripe for Bates, an award-winning author and journalist, to put the evidence under a 21st-century microscope.

The result of his research is a gloriously engaging romp revolving around a knotty case that boasts all the ingredients a crime fiction fan could hope for — an inconvenient wife, an apparently cunning husband, poisoned chocolates, a pipe-smoking detective and an excitable judge who itches to don his ominous black cap. Only, as Bates gradually and deliciously reveals, the major, who endured a harrowing trial in the spotlight and went to his death still protesting his innocence, may not have committed the crime at all.

What happened after the 48-year-old passed away in sleepy Hay-on-Wye fueled the creative minds of Agatha Christie, Dorothy L Sayers and Georgette Heyer.

Katharine Armstrong died barely three years after the Great War had ended, in the middle of an influenza epidemic and shortly after another alleged spousal poisoning, one that ended in a controversial acquittal. All the above played into an investigation brimming over with circumstantial evidence and crass assumption.

The prosecution at the trial placed great weight on the account of Oswald Martin, a rival solicitor to Major Armstrong who worked for a firm across the street. Martin claimed to have been the victim of a bungled poisoning attempt at Armstrong’s hands.

Soon after Katharine’s apparently natural death, the widowed major had invited Martin to afternoon tea. During the meal Armstrong placed a particular scone on his guest’s plate, with the polite comment: “‘Scuse fingers.” Martin ate the scone and, within hours, fell violently ill. Weeks earlier, it was revealed, his household had taken delivery of a mysterious box of chocolates that, when eaten, had caused similar symptoms. Armstrong was opposing Martin in a local legal matter — was he making repeated efforts to do away with his rival?

Arrested for Martin’s attempted murder, Armstrong denied all charges; his defense would argue that Martin had greater cause to want rid of Armstrong than vice versa. Then the arsenic came to light. Lots of it. Some in small packets concealed in the major’s bureau drawer, some in an overcoat pocket. Armstrong tried to explain away the damning evidence as ingredients for homemade weed killer. But who needs weed killer in February?

The police by this time had already thought beyond the poisoned scone, back to Katharine’s death. Bates describes in colorful detail the exhumation and postmortem examination of her body, and presents a comprehensive account of the ten-day trial that began on April 3, 1922.

Then the arsenic came to light. Lots of it.

As the world’s press descended on Hay, the major found himself the subject of speculation not just about the fatal levels of poison discovered in his wife’s body, but about his behavior and demeanor. He had taken a Continental holiday soon after Katharine died. Was he a wife-killer enjoying newfound freedom, or a lonely widower trying to lift his spirits? Was this calm, well-spoken figure a callous man with no remorse, or was he remorseless simply because he was innocent and trusted the legal system to find him so?

One of the strengths of The Poisonous Solicitor is the way it places the case of the Hay Poisoner in the context of what came after the hanging of Armstrong on May 31, 1922. The story certainly reads like a blueprint for the Golden Age of crime writing that followed, with their twisting stories and grisly murders pitched to maximize the puzzle and minimize emotional engagement with the victims. Murderers in these novels were people from the professional classes who acted on clear and rational motives. Detectives were brilliant policemen or eccentric amateurs who could outthink the craftiest villain.

Queen of the genre Agatha Christie was an expert on poisons and one can well imagine her fascination with Major Armstrong. Strikingly, her 1939 novel Murder Is Easy depicts a woman’s death that is at first thought to be natural, but is later found to be a poisoning after other suspicious deaths come to light.

And Christie wasn’t the only “fan” of the Armstrong case. In Unnatural Death, published in 1927, Dorothy L Sayers refers to the major by name — in a list of criminals who made fatal errors. In Strong Poison (1930) a solicitor feeds a rival arsenic-laced omelettes. And Georgette Heyer, whose first novel appeared the year Katharine died, would also mention the case in Detection Unlimited (1953), published at the tail end of the Golden Age.

As for whether Armstrong did it or not, Bates executes a thorough and balanced examination of the facts — but like all great whodunits, the twist is on the final page.

Janice Hallett is the author of The Appeal and The Twyford Code