There was, it seems, at least some truth to Petiot's later claims of joining the Resistance. Soon after the Nazi occupation of Paris, he began providing false medical certificates to Frenchmen drafted for slave labor. Petiot also apparently treated sick and wounded workers returned to France from Germany, gleaning information about Nazi troop movements and weapons development. His Fly-Tox network, named after a popular insecticide (since informers were dubbed "flies"), spied on Gestapo headquarters in Paris to identify collaborators so they could be eliminated by teams of Resistance assassins.
Victims 1 : Joseph Réocreux, François Albertini, Adriene Estébétéguy, Claudia Chamoux, Annette Basset, Gisèle Rossny / Victims 2: Nelly-Denise Hotin, Dr. Paul-Léon Braunberger, Joseph Piereschi, Joséphine-Aimée Grippay (aka Paulette Grippay)
At the same time, though, Petiot spun tales of patriotic battles that were never fought. He claimed to have invented "secret weapons" that killed Nazis without forensic evidence. Allied commanders denied his reports of high-level meetings and no evidence of the mystery weapon ever surfaced. Petiot also claimed to be working with a group of anti-fascist Spaniards in Paris, but they were never found. His tales of planting bombs and booby traps around Paris were fervid flights of fantasy.
Petiot's chief operation after 1940 was disclosing escape routes to potential fugitives. He welcomed Jews, Resistance fighters, petty criminals — anyone, in fact, who could meet his price of F25,000 a head. For that amount, Petiot promised safe passage to South America, complete with all the necessary travel papers. In 1941 he bought the house at 21 Rue le Sueur, as a way station for his personal Underground Railroad.
Among Petiot's early customers were two Parisian pimps, Joseph Réocreux and Adriene Estébétéguy, who had lately broadened their repertoire to include armed robbery while disguised as Gestapo agents. Sought by French and German police alike, Réocreux sought help from Petiot (known as "Dr. Eugène" to his illicit clients) in September 1942. Traveling with his mistress, Claudia Chamoux, and another couple — pimp François Albertini and prostitute Annette Basset — Réocreux paid his fee and promptly vanished into 21 Rue le Sueur. Estébétéguy and girlfriend Gisèle Rossny followed in March 1943, also vanishing without a trace. Petiot would later boast of killing the three pimps and their women, branding all six as Nazi collaborators, touting their executions as his patriotic duty.
By April 1943 Gestapo officers reported "a great deal of talk in public about an organization which arranges clandestine crossings of the Spanish border by means of falsified Argentinean passports." Nazis asserted that "the voyagers travel on neutral ships leaving from a port in Portugal." In fact, they never left Paris alive. Gestapo agent Robert Jodkum blackmailed a French Jew, Yvan Dreyfus, into approaching the network for passage, but Dreyfus vanished with the rest in May 1943.
Others who availed themselves of Dr. Petiot's services included Nelly-Denise Hotin, a pregnant newlywed who came looking for an abortion in July 1941 and was never seen again. Dr. Paul-Léon Braunberger, an elderly Jew who planned to flee with his wife, disappeared alone from a Paris subway station in June 1942. A month later, three German Jews — the Knellers — vanished after consultations with Petiot, their dismembered remains fished out of the Seine in August. Three more refugees, the Wolff family, disappeared into 21 Rue le Sueur, along with six friends. Another pimp, Joseph Piereschi, also made the dead-end journey with his mistress, Joséphine-Aimée Grippay.
Those were the victims whom police later identified, but they did not comprise the total body count. Numerous dismembered victims were dragged from the Seine in 1942 and '43, the remains including nine heads, four thighs, and sundry other mutilated pieces. French police and coroners were baffled, unable to identify most of the dead. Gestapo agents, for their part, were less concerned about dead Frenchmen than about the prospect of Jews and Resistance fighters escaping to freedom. The Nazis had a fix on Petiot's Fly-Tox network, and by May 1943 they were ready to spring the trap.