She was born Jeanne Moulinet at Poligny in the Jura on October 7, 1874, came to Paris as a teenager, married a labourer named Weber and lived in the Goutte d'Or. Two of her own three children died young.
In March and April 1905 four children died in her care in the family's building: her nieces Georgette and Suzanne Weber, her sister-in-law's daughter Germaine, and her own son Marcel. In each case she had been alone with the child, and in each case there were marks on the throat. She was charged in the deaths and tried in 1906. The French press called her the Ogress.
The trial turned on the evidence of Leon Thoinot, one of the most eminent forensic physicians in France, who examined the bodies and testified that the children had died of natural causes and that the marks were not signs of strangulation. She was acquitted to public acclaim and the press treated her as a woman wronged by suspicion.
She then killed again. In April 1907 a nine-year-old boy, Auguste Bavouzet, died while she was working for his family in the Indre under an assumed name; Thoinot was consulted again and the case collapsed again. In May 1908, at Commercy, she was caught in the act, found in a room with the strangled body of a seven-year-old boy, Marcel Poirot, with the mother and a doctor at the door. Even then Thoinot maintained his position.
She was declared insane on October 25, 1908 and committed to the asylum at Mareville, where she died on July 5, 1918. A death date of 1910 is one of several circulating; 1918 is the date given in the French records.
The count is uncertain, and the dispute behind it is real rather than a matter of sloppy record-keeping: the acquittals mean that most of the deaths were formally found to be natural, and Thoinot never withdrew. The case is taught in the history of forensic medicine as the clearest example of an expert's authority outweighing the evidence in front of him, and children died in the gap.