French mistress of serial killer Henri Désiré Landru (1869-1922) who murdered at least seven women in the village of Gambais between December 1915 and January 1919.
Segret, a lyric artist, met Landru in May 1917: he was sitting opposite her in a streetcar and approached her after she arrived at her destination at Galeries Lafayette. Using the false name of Lucien Guillet, Landru succeeded in eventually convincing her to marry him. She became his mistress from the end of July 1917, but Landru constantly managed to delay the wedding on the pretext of the German occupation which prevented him from obtain the necessary papers. At Easter 1918, she and her mother eventually realized that the alleged industrialist de Rocroy (Rocroi) was not who he claimed to be, after they made contact with the mayor of the town, who did not know anyone under that name. Yet their engagement took place in May 1918. The wedding should have followed at the end of the year, to be finally set at the end of the month of February 1919, but it did not take place under the pretext of documents still inaccessible. This did not prevent her from settling into a common law marriage with Landru at 76 rue Rochechouart in Paris.
They were still living in a conjugal relationship at the time of his arrest in 1919. She claimed during the investigation that he had tried to poison her twice. After the trial, she made a career in a Parisian cabaret, then went to work as a teacher in Lebanon.
She was portrayed by actress Stéphane Audran in Claude Chabrol’s French-language film Landru (1963), from a script by the novelist Françoise Sagan. Segret sued Chabrol for defamation because she disapproved of her portrayal in the film. Segret received modest damages (10,000 francs) and retired to a care home in the town of Flers.
On the anniversary of Landru’s marriage proposal, she committed suicide on 21 January 1968 at age 75 by throwing herself into the moat of the Château de Flers.
Link to Wikipedia biography (French)