Documents in the Case by Sayers And Eustace

 Sayers wrote only one detective story which was not a Lord Peter work.  She produced a work called Documents in the Case, which was based on the murder case of Edith Thompson and Frederick Bywater, in the 1920s.  

A few detective writers of the time wrote fictionalised versions of the story, but Sayers chose to write a more complicated work which involved a lot of scientific input for the murder method. She worked in collaboration with a doctor, Eustace who supplied her with information on mushrooms and poisons.  The story is set in Bayswater, in a suburban maisonette, where a Mr Harrison and his young second wife live.  Harrison is an engineer, rather a bore, but a decent enough man, but he nags his wife, who is getting fed up with him.  Two young men move into a flat in the top of the house, a writer and a painter, (Munting and Harwood Lathom). 

Margaret Harrison increasingly bored with her husband, starts an affair with Lathom.  Munting disapproves of his friend seducing a married woman whose husband has been friendly to Lathom.  He leaves the flat and gets married, and some time later, he meets Lathom again, who has picked up his friendship with Harrison. Margaret thinks she is pregnant and is scared to death.  Lathom resolves to free her from her marriage. 

He goes off on a painting holiday with Harrison, in a cottage down in the West country, and goes back to London on business.  He meets Munting and invites him to come down for a couple of days and when they get there they find Harrison has died horribly from poisoning, apparently from cooking and eating some poisonous mushrooms that he has foraged locally.  

Paul, Harrison's son by his first marriage, does not believe that his father would make a mistake like that over food, and thinks that he has committed suicide to free his wife from their marriage, as he knows of the affair. He reads up the letters he has had from his father and other documents and finds that it is not suicide or accident, but murder.  Lathom used artificially made poison to kill Harrison, while providing himself with an alibi. Paul gets hold of the love letters written by Margaret to Lathom, by bribing Lathom's charlady, and finds that she thought she was pregnant and was urging her lover to "do something" to help her. 

He puts together a case, and the police investigate it.  Margaret (unlike Edith Thompson) is considered innocent, in spite of her compromising letters but Lathom is found guilty of murder and hanged.  The book is not one of Sayers' best.  It starts with a fairly sympathetic portrayal of Margaret, as a lonely wife whose husband nags at her, is suspicous of her and generally is not a sympathetic character.  Then sympathy abruptly switches to Harrison, who is seen as a victim of his wife's shallowness and Lathom's selfishness. Sayers never wrote another non Peter detective work again.