|“||He was an evil man.||„|
|~ Madame Déroulard revealing her son's true nature|
Madame Déroulard is a major protagonist in Agatha Christie's Hercule Poirot short story, "The Chocolate Box", which would be included in Poirot's Early Cases in 1974.
Madame Déroulard was a Belgian diplomat and the mother of the tyrannical and treacherous Paul Déroulard, being the story's culprit responsible for killing her own son. However, she killed her son for sympathetic and understandable reasons, in order to both avenge her murdered daughter-in-law, Marianne Déroulard, and to protect Belgium after discovering her son to be an espionage to the German Empire.
She was portrayed by the late Rosalie Crutchley in Agatha Christie's Poirot.
Some years before, Madame Déroulard saw her son, Paul, push his wife down the stairs and realised Afraid of the persecution that her son’s new role would bring upon the church and for his approaches to the innocent Virginie, she resolved to kill her son. She stole John Wilson's tablets. She opened the new box of chocolates before seeing that the previous box was not yet empty.
After inserting about 20 tiny tablets in one chocolate, Madame Déroulard took the opportunity to place the empty bottle into M. de Saint Alard's pocket when he came to say his farewell, thinking that his valet would throw it away. Nevertheless, her poor eyesight would cause her, and only her, to swap the lids and placed the wrong lid on Paul's chocolate box.
During the investigation, Poirot mistook Saint Alard was the culprit due to his immaturity of psychology analysis, until he discovered the poor eyesight of Madame Déroulard. She directly confessed to Poirot and Virginie Mesnard about being the killer and revealed Paul's true nature as both a traitor and a murderer, before revealing her failing condition. Poirot decide not to arrest Madame Déroulard.
A week after Poirot wrapped up his investigation, Madame Déroulard died of her infirmities. As Captain Arthur Hastings had discovered, the nearly failed investigation of Paul Déroulard's murder would always be considered by Poirot himself as his greatest failure in his career ever.