Dr. Marcel Petiot was a Parisian physician during World War II who would come to be known as the "Vampire of the rue Le Sueur." In the 1930s Petiot was found not guilty by reason of insanity in a shoplifting charge. As part of his sentence, Petiot's wife admitted him to a state mental hospital. Petiot explained to the psychiatrist that he had invented a cure for constipation and took credit for astrophysical theories. The presiding psychiatrist diagnosed Petiot with what we would refer to today as manic depression

Petiot returned to his professional career as a physician in the general practice of medicine, but he also treated several patients for drug addiction. In 1942, Petiot had a narcotics charge pending against him. Mysteriously the two individuals scheduled to testify against him disappeared. The two witnesses were later found dead and thought to be Petiot's earliest victims.

Two years...