"The Croydon Arsenic Mystery" by Diane Janes

On 5th March 1929, in South Croydon, Violet Sidney died. Analysis of her remains suggested arsenic poisoning. Given that her daughter, Vera, had died a few months before and her other daughter Grace's husband shortly before that, their corpses were exhumed and found to contain arsenic. The suspects included the cook, the doctor (who was rumoured to fancy the widowed Grace), the Grace herself, and the son, Tom. It was a classic middle class murder mystery.

But was it? Although eminent forensic scientist Sir Bernard Spilsbury convinced the coroner that arsenic was involved in all three deaths and although Inspector Hedges, the local flat foot, was convinced of Grace's guilt, the police never prosecuted anyone.

Ms Janes follows the twists and turns of this case, through three inquests which sometimes threatened to slip from the coroner's control, through the brow-beating of suspects in a scarily biassed investigation, and through details of a forensic science that was still in its infancy. She castigates the police and the expert witnesses as asserting much much more than they could possibly prove, she shows how one of the analysts added his numbers up wrongly in a document that was provided to the court and never challenged, and she suggests her own unique solution.

She is certainly thorough. This is rather at the expense of clarity. There were so many assertions and challenges during the inquests, which were interleaved in time, that it becomes extremely confusing for the general reader. Much of the first two thirds of the book is devoted to a narrative reconstructing these details. But the book itself only comes alive when she shows how the evidence is flawed and when she looks at each death separately from a more modern perspective. When she sweeps aside the irrelevancies of description, the solutions she proposes become highly probable.

If she had restricted herself to the explanation part of the book it might have been a lot shorter but it would have been a great deal better. October 2015; 195 pages