Armed with his new medical degree, Petiot moved to Villeneuve-sur-Yonne, an ancient village on the Yonne River, 25 miles from Auxerre. On arrival, the 25-year-old physician printed fliers comparing himself to the town’s two elderly doctors. The fliers read: “Dr. Petiot is young, and only a young doctor can keep up to date on the latest methods born of a progress which marches with giant strides. This is why intelligent patients have confidence in him. Dr. Petiot treats, but does not exploit his patients.”

In fact, while outwardly charming and popular with most of his patients, Petiot secretly enrolled them for state medical assistance, thereby insuring that he was paid twice for each treatment--once by the patient and once by the government. He favored addictive narcotics in his prescriptions. When one pharmacist complained of the near-fatal dose Petiot prescribed for a child, Petiot replied, “What difference does it make to you, anyway? Isn’t it better to do away with this kid who’s not doing anything in the world but pestering its mother?”

Dr. Marcel Petiot, police mugshot

In private, Petiot remained a loner who turned casual conversations into heated debates, ever insisting on the last word. He lived modestly, but splurged on a sports car which he drove recklessly through Villeneuve-sur-Yonne, causing numerous traffic accidents. A confirmed thief, Petiot stole from strangers and relatives alike; brother Maurice insisted on searching his pockets every time Marcel visited his home. Evicted by one landlord for theft of furniture and fixtures, Petiot shrugged off threats of litigation with the remark that as a certified lunatic he could never be convicted.

Around the same time, in March 1922, Petiot clashed with the Commission de Réforme over demands for new psychiatric exams to maintain his disability payments. He declared that he “purely and simply refused to accept any disability pension at all so as to avoid being subjected to what I find a more than disagreeable bit of exhibitionism.” Still, the checks kept coming and he was examined once more in July 1923, doctors reporting that his tongue was scarred from bite wounds during epileptic seizures and that Petiot evinced “total indifference” about his own future. That said, his disability was reduced to 50 percent.

In 1926 Petiot surprised his neighbors by launching a torrid affair with young Louise Delaveau, the daughter of Madame Fleury, an elderly patient. Soon after the affair began, the Fleury home was burglarized and set afire. No one connected the events, but Petiot was suspected when Louise disappeared in May 1926. Neighbors recalled seeing Petiot load a large trunk into his car, closely resembling another fished out of the river weeks later, filled with the dismembered, decomposed remains of a young woman who was never identified. Ignoring the “coincidence,” police searched briefly for Louise and then dismissed her as a runaway. She may, in fact, have been Petiot’s first murder victim.

Soon after Louise disappeared, Petiot ran for mayor of Villeneuve-sur-Yonne. The long, bitter campaign climaxed in July 1926, when Petiot hired an accomplice to disrupt a political debate with his opponent. When Petiot finished speaking, his crony cut power to the auditorium, blacking out the entire village and starting several fires. Petiot won by a landslide. His opponent later told the Commission de Réforme that Petiot had boasted of feigning insanity to escape military service. Yet another review of his case confirmed the original diagnosis, pronouncing Petiot’s claims of fraud “another manifestation of the subject’s mentally unbalanced state.”