On September 30, 1936, at the funeral of an elderly Liege woman named Florine Lange, one of the mourners was a fifty-seven-year-old widow, Marie Becker, who took two of the other mourners, Madame Weiss and Madame Lamy, home with her for something to drink. Marie Weiss, sixty-two, died on October 2. Digitalis poisoning brings on agonizing stomach cramps and death within one to four days, long enough for victims to talk, and both Lange and Weiss had said they could not keep down the tea a friend had served them. The friend was Marie Becker. Autopsies of the two women on October 12 found nothing, but the police began watching her.
She was born Marie Alexandrine Petitjean in the village of Waasmont, in the municipality of Landen, on July 14, 1879. She rarely went to school, working her parents' fields, and asked the village priest to teach her to read, write and count. At sixteen she went to live with an aunt who kept a rope shop on the rue Saint-Pholien in Liege. In 1900 she went to work in a sewing shop, and she rose to managing the fittings at a large fashion house on the rue du Pot d'Or. In 1906 she married Charles Becker, and the couple lived beside the family sawmill. In 1920 she opened her own fashion business on the rue Saint-Leonard, employing four workers. In 1928 she took a lover twenty years younger, Maximilien Houdy, and poured money into him. The 1929 crash and her spending finished the shop, which was declared bankrupt in 1934.
Charles Becker died in October 1932 or 1933; three doctors testified that he had cancer, and that the cancer killed him, though some later accounts make him her first victim. From 1933 she worked by the day as a seamstress for wealthy clients and then as a nurse and companion to well-off widows, borrowing money from them or stripping them of securities and jewelry. Her first known victim, Marie Doupagne-Castaldot, died on March 21, 1933, after drinking tea Becker had made; she had lent Becker 1,200 francs. Lambert Beyer died on November 2, 1934, after making a will in her favor. The others included Julie Bossy, who called the tea she had been given abominably bad; Catherine Beeken-Poirot; Aline Louis-Damoutte; Marie Remacle; Marie Evrard-Crulle; Marie Stevart; Florine Lange; and Marie Luxem-Weiss, the eleventh. Five more survived, among them her landlady, Marie Bouille, who took one sip of a bitter tea and then watched in surprise at how hard Becker scrubbed the two cups.
Lamy was next. Becker announced a visit to her for October 16, 1936, and the police were waiting. In her handbag they found a small vial of digitalis, a drug that strengthens the heart drop by drop and can kill in a larger dose; at her flat at 16 rue Donceel, across from the collegiate church of Saint-Denis, a large bottle was hidden in an armchair. Investigators later found victims' jewelry, and seventeen vials of digitalis she had no medical need for. The investigation took seventeen months and changed Belgian practice in forensic medicine and toxicology. She never confessed to anything.
The trial ran before the Liege Assizes in the palace of the Prince-Bishops from June 7 to July 8, 1938, with some sixty character witnesses; the young Georges Simenon covered it. She seemed to enjoy herself, and at one point the presiding judge told her she looked as if she were having a fine time. She was convicted of eleven murders, five attempted murders, theft and forgery and sentenced to death, commuted to life imprisonment as had been the practice in Belgium since 1863. Her contemporaries called her the poor man's Brinvilliers. She died in Forest prison in Brussels on June 11, 1942, under the German occupation.