Sheringham is interested in the much-publicized upcoming trial of Mrs. Jacqueline Bentley, who is charged with the murder of her husband John by poisoning with arsenic.

She claims she cannot account for the arsenic being in the thermos residue and in some medicine bottles and suggests that Bentley himself was responsible for adding it in these cases.

Sheringham concludes: “Bentley died from natural gastroenteritis set up either by the chill he had caught at the picnic or by impure food, and possibly (one might say, probably) aggravated by the arsenic with which he at once proceeded to treat himself.”[3] Martin Edwards observes that Berkeley and his contemporaries Agatha Christie and Dorothy L. Sayers “were fascinated by murder in real life.

Sheringham also alludes to numerous other true crime cases involving Edith Thompson and Frederick Bywaters, Frederick Seddon, Hawley Harvey Crippen, William Palmer, Edward William Pritchard, George Henry Lamson, Herbert Rowse Armstrong, Catherine Wilson, Maria van der Linden-Swanenburg (referred to in the novel as “Van de Leyden”), Marie Jeanneret (a Swiss nurse found guilty of murdering six persons and attempting to murder two others by poison), Steinie Morrison, Oscar Slater, Constance Kent, Alfred John Monson, and Madeleine Smith.

The circumstances of the case, the methods of the murder, the steps he tales to elude detection—all these arise directly out of character; in themselves they’re only secondary.