She did administer the fatal insulin injection. The others suspect her of killing Aristide, especially Roger, who denounces her as a gold-digging slut and certainly guilty. Aristide's second wife, Brenda, is much younger, a former Las Vegas casino dancer. His domineering wife Clemency is a plant biologist with extensive knowledge of poisons. The younger son, Roger, is managing director of a major family business, but is a failure, requiring multiple bail-outs from Aristide. Philip and Magda provided Aristide with three grandchildren: Sophia, Eustace (a teenager crippled by polio, who believes his grandfather despised him), and Josephine (a clever 12-year-old, who spies on everyone and writes it down in her notebook). Aristide's elder son, Philip, hated his father for passing him over as successor to the family business, and for refusing to fund production of a screenplay Philip wrote for his wife, Magda, a fading theater actress. Edith stalks around the grounds, blasting moles in the lawn with a shotgun.

She despised her brother-in-law as a parvenu and for his callousness towards his grandchildren.

Lady Edith de Haviland was the sister of Aristide's late first wife she moved in to care for her motherless nephews. All of them resented the way he bullied and manipulated them. All of them knew about the eserine: Aristide talked about how it could be used to kill him. All of them get substantial bequests from Aristide's estate. At the Leonides estate, Charles interviews the various members of the family, finding motives for each of them. Charles seeks the consent of Chief Inspector Taverner of Scotland Yard to look into the case, utilizing his personal connection with Taverner, who had served with Charles's father, a decorated former Assistant Commissioner who was murdered. Charles reluctantly takes on the case, in part because he had a brief love affair with Sophia in Cairo. Sophia believes this was deliberate, not accidental.

Sophia notes that Aristide' regular insulin injection had been laced with eserine from his eye drops, causing a fatal heart attack. Sophia wants Charles to investigate Aristide's death, for she believes he was murdered by a member of his sprawling and idiosyncratic family. The granddaughter of late Greek-British business tycoon Aristide Leonides, Sophia Leonides, visits private investigator Charles Hayward in his office.

Crooked house plot