Maigret - Landru

Henri Landru enticed women with offers of marriage and killed them after he had stripped them of all their assets. He was tried at the Seine-et-Oise Assizes Court and on being found guilty was sentenced to death for the murder of eleven women. On February 25, 1922 he was guillotined. (The Paris press was convinced that public opinion was as excited about the Stavisky-Prince affair as it had been by the cases of Landru and Violet Nozières. Assouline p.123. )
In the 1943 L'Inspecteur Cadavre [M's Rival]
The doctor said he remembered that M had solved the Landru case, one that M had had nothing to do with.
In the 1950 Les mémoires de Maigret [M's Memoirs]
In the space of half a century, there hadn't been more than a score of sensational cases, including the Bonnot case, the Mestorino case, the Landru case, the Sarrat (sic) case, and a few others....
In the 1951 Maigret, Lognon et les gangsters [M and the Gangsters]
M felt like answering, "And Landru? Was that child's play too?"

NOTE: "Sarrat" is a typo appearing in the English translation for "Sarret".