The Deadly Seidlitz Powder

When someone is murdered by poison, it can often be difficult to determine who was responsible for the fatal dose, but at least investigators generally are able to find possible motives for the crime.  However, if it is hard to determine not only who poisoned the victim, but why…then you really have a problem.  Such was the mystery plaguing the police of Sydney, Australia in 1932.

33-year-old Dorothy Florence Thorne lived with her husband of ten years, Reginald, who was a successful motor engineer, and their infant daughter Joan.  A recent addition to the household was a boarder, Alfred George Lockyer.  Lockyer was an English-born commercial artist who was having trouble finding work, which led to him falling into a deep depression.  Reginald became friends with Lockyer, and, out of sympathy for his plight, invited the artist to room with his family.

The small household appeared to be an enviable one.  Dorothy was a charming, amiable woman who was extremely popular in the neighborhood.  Her marriage was happy, and both she and Reginald were deeply devoted to their little girl.  Lockyer seemed an ideal boarder--good-natured, unobtrusive, and helpful around the house.  He readily did little chores around the house, such as preparing the morning tea and toast for the family.

On the morning of July 5, 1932, Dorothy happened to be the first one awake.  As she passed Lockyer’s room, she playfully called to him, “I’ve beaten you to it this morning!”  A few minutes later, she returned to Lockyer’s door in a much changed mood.  She told him that she had taken a seidlitz powder from the tin in the kitchen, and it tasted strangely bitter.  Lockyer took a small taste from her glass, and was startled by the extreme bitterness.  They both shrugged at the little mystery, and Dorothy returned to the kitchen.

Lockyer brought Reginald, who was still in bed, a cup of tea and a slice of toast.  When he went back to the kitchen, he was shocked to see that Dorothy was having some sort of fit.  She was staggering wildly around the room, her face was twitching, and her eyes had gone blank.  Assuming that her sudden illness was related to the strange-tasting seidlitz powder, he sat her on the chair and gave her an emetic of mustard and water.  By the time he called Reginald into the kitchen, Dorothy was suffering agonizing convulsions.  The family physician, Dr. Pawlette, was instantly summoned.  As soon as Pawlette saw Dorothy, he wasted no time driving her to the hospital.  However, before he even reached the hospital, the poor woman was dead.

Naturally, there was an inquest, where the city coroner, Dr. May, soon realized he had a fine mess on his hands.  It was quickly determined that Dorothy had died as a result of drinking a seidlitz powder that had been liberally laced with strychnine.  That proved to be the one undeniable conclusion in the case.  Suicide was safely ruled out.  It was established that when Reginald bought the powders from a local chemist, they were poison-free, meaning that someone with access to the Thorne household had subsequently tampered with them.  Only one package of the powders in the tin had been doctored with strychnine--the one Dorothy had the appalling bad luck to swallow.

The source of the strychnine was never found.  Neither was the motive.  Reginald Thorne seemed genuinely shocked and heartbroken by his wife’s sudden death.  Dorothy’s relations with Lockyer appeared to be friendly, but with no hint of, in the words of the time, “undue familiarity.”  Dorothy came from a well-off family.  In her will, she left Reginald all her property, which amounted to some shares in the businesses operated by her husband and her father, as well as a small amount of money in the bank.  It was not seen as worth killing her for it, especially as Reginald was making a good living of his own.  It was not even clear that Dorothy was the poisoner’s intended victim, as she only rarely took seidlitz powders.  Was the strychnine meant for Reginald?  Or Alfred?  No one could say.

After all the witnesses had testified, the coroner admitted defeat.  “In all my experience,” he sighed, “I have never had a case more mysterious than this. I intend to exclude the husband and the boarder.  I have watched them carefully. Their whole attitude, from the time before the doctor was sent for and since, seemed to point to nothing else but innocence. I also exclude any idea of suicide. The extraordinary thing is: How did this poison get there as it did?"  

He concluded, “I am wording my finding in such a way as to leave an open verdict. The husband and the boarder are exonerated.  In so far as the firm and the chemist are concerned, there is nothing to show that there was any tampering with the powders before they set out. The whole thing is a mystery, and we would be very pleased if that mystery could be solved.”

He found that the poison had been accidentally self-administered by Dorothy but the evidence did not enable him to say whether the strychnine was “feloniously mixed” with a seidlitz powder.

That was the last official word on the case.  In 1934, Reginald and his daughter went back to his native England, where they lived with his sister until his death in 1945.  He never remarried.

The poisoning of Dorothy Thorne is one of those cases where the story feels only half-told.  Unfortunately, the other half seems likely to be permanently unrevealed.