Murder in Mesopotamia

Nurse Amy Leatheran arrives at an archaeological dig near Hassanieh, Iraq, to assist the Swedish-American archaeologist, Dr Eric Leidner, in caring for his seemingly-neurotic wife, Louise. During her initial days, Amy learns that Louise was married before to a German named Frederick Bosner. Fifteen years ago, during the Great War, Bosner was arrested for being a spy within the US State Department, and sentenced to death; he escaped custody, but died later in a train crash. Louise reveals that she received death threats claiming to be from Frederick, whenever she was attracted to another man; these stopped when she married Leidner three years ago, until recently. A week later, after receiving another threatening letter, Louise is found dead in her bedroom in the archaeologists' compound near the dig site. Dr Giles Reilly determines she was struck by a very heavy, blunt object.

An initial investigation, led by Captain Maitland, cannot find the murder weapon, but confirms someone on the dig must have committed the murder. Reilly learns that his friend Hercule Poirot is travelling in Iraq, and so contacts him for help. When Poirot arrives, he notes that the bedroom has only one point of entry, that the only window in the room was shut and barred, and that a rug near a washstand has blood on it. Anne Johnson, a colleague of Leidner, claims she heard a cry, yet is unsure about it. Reilly's daughter Sheila remarks that the victim had the attention of every man, especially one of Leidner's old friends Richard Carey. Poirot takes an interest in the story Louise told Nurse Leatheran about her first husband; he wonders if Bosner, or possibly his much-younger brother William (presumably still living but whereabouts unknown) is somehow among the team. Two men – epigraphist Father Lavigny and drug-addicted historian Joseph Mercado – are the right age to be Frederick. Furthermore, three younger men – dig assistants Bill Coleman and David Emmott, and photographer Carl Reiter – are the right age to be William. Reiter in particular is of German-American ancestry, and was tormented by Louise for his shyness and clumsiness. However, he seems to have an alibi. Poirot is also intrigued to find that the letters Louise received were apparently in her own handwriting.

Following Louise's funeral, Nurse Leatheran meets with Miss Johnson on the compound's roof. Johnson claims she knows how someone could have entered unseen, but does not elaborate further. That night, Miss Johnson unwittingly drinks a glass of hydrochloric acid which had been substituted for her usual glass of water on her nightstand. Amy attends to Miss Johnson, and hears her mention "the window" before she dies. The nurse does not believe Miss Johnson has committed suicide, and wonders if she hinted at how the acid was switched for the water. After spending a day sending telegrams, Poirot brings everyone together and reveals that both women were murdered by Dr Eric Leidner, who is, in reality, Frederick Bosner. The real Leidner died in the train crash 15 years ago – when Bosner came across his body and found his face disfigured, he switched their identities to escape the authorities.

Bosner was deeply possessive of Louise. To discourage her from forming relationships with other men, he sent her letters, which he carefully wrote out in her handwriting so the police would disbelieve her. The letters stopped after he married her twelve years later, when she no longer recognised him. When Louise became attracted to Richard Carey, Bosner decided to murder her to ensure no one else could have her. On the day of the murder, Bosner, on the rooftop, lured her to the window with a mask he had used to scare her on previous nights. Once she stuck her head out to investigate, he dropped a quern on her, which he then pulled back to the roof via a rope he had tied to it. On the pretense of checking on her, he shut the bedroom window while moving the body and the rug beneath it to where they were later found. He then used Amy as part of his alibi to divert suspicion from himself. Miss Johnson was murdered because she had begun to realise how Louise was killed.

In the aftermath of Poirot's investigations, it is revealed that Father Lavigny is actually Raoul Menier, a dealer in stolen artifacts. As Lavigny was known to Leidner only by reputation, Menier was able to impersonate him while stealing artifacts found at the dig and replacing them with excellent copies. Thanks to warnings sent out by Poirot, Menier and his associate Ali Yusuf are arrested in Beyrouth. Sheila marries David Emmott, and Nurse Leatheran returns home to England.