In 1851 a maid named Rosalie Sarrazin fell ill in the Rennes household of Théophile Bidard, a law professor at the university, and died. A year earlier another of his servants, Rose Tessier, had died the same way, with the same cook, Hélène Jégado, tending her at her bedside. The two doctors who had tried to save Rosalie saw the likeness and persuaded her family to allow an autopsy. When the police came, Jégado declared her innocence before anyone had accused her of anything. She was arrested on July 1, 1851.
She was born around 1803 on a small farm at Plouhinec, near Lorient in Brittany. Her mother died when she was seven, and she was sent to work with two aunts who were servants at the rectory of Bubry. Seventeen years later she followed an aunt to Séglien and became cook to the curé there, where she was accused of putting hemp from his grain store into his soup.
In 1833 she went to work for another priest, Father François Le Drogo, in the village of Guern. Between June 28 and October 3, seven people in the household died suddenly: the priest, his elderly mother and father, and her own visiting sister, Anne Jégado. The cholera epidemic of 1832 was fresh in memory, and her grief and piety were so convincing that no one suspected her. She went back to Bubry to take her sister's place, and within three months three more people died, her other aunt among them, all nursed by her. At Locminé she lodged with a seamstress, Marie-Jeanne Leboucher; mother and daughter died and a son fell ill, perhaps surviving because he refused her care. The widow Lorey, who took her in next, died after eating a soup she had made. In May 1835 she was hired by a Madame Toussaint, and four more died. By then, by the later count, seventeen people were in their graves.
She was dismissed from a convent at Auray for vandalism and sacrilege, and cooked briefly in houses in Auray, Pontivy, Lorient and Port-Louis, where people often fell ill or died. Among the dead was a small child, Marie Bréger, at the Château de Soye near Ploemeur in May 1841. She was never caught with arsenic, though most of the dead showed its symptoms. From late 1841 to 1849 no suspected deaths are recorded, only thefts; she stole compulsively. In 1849 she moved to Rennes.
Later inquiries linked her to twenty-three deaths between 1833 and 1841, but they lay outside the ten-year limit on prosecution and there was no scientific evidence, so her trial, which opened on December 6, 1851, dealt only with three murders, three attempted murders and eleven thefts. One further case was apparently dropped because it involved a child and the police did not want to put the parents through an exhumation. The recent victims, exhumed, showed overwhelming evidence of arsenic and possibly antimony; Faustino Malaguti, a chemistry professor at Rennes, testified as an expert. In court she swung between humble muttering, loud pious outbursts and violent attacks on her accusers, and insisted she did not know what arsenic was. Her lawyer, Magloire Dorange, argued in closing that she needed more time than most to repent and could be spared because she was dying of cancer anyway.
She was sentenced to death. The case drew little attention at the time, pushed from the front pages by the coup d'état in Paris. On February 26, 1852, she was guillotined before a large crowd on the Champ-de-Mars in Rennes. Folklore has since attached many unexplained deaths to her, some surely natural; the most reliable estimate is that she killed about thirty-six people.