Nr 1 2012 av “Världens Historia” har en stor åttasidig artikel om den franske detektiven Eugène Vidocq (1775-1875) som på många sätt var en verklighetens Sherlock Holmes. Hans gärningar inspirerade författare Émile Gaboriau till historierna om monsieur Lecoq. Även Edgar Allan Poe lät sig inspireras av Vidocq när han skapade figuren C. Auguste Dupin.
Conan Doyle var förstås påverkad av både Lecoq och Dupin, även om han lät Sherlock Holmes påskina motsatsen i “A Study in Scarlet”:
Sherlock Holmes rose and lit his pipe. “No doubt you think that you are complimenting me in comparing me to Dupin,” he observed. “Now, in my opinion, Dupin was a very inferior fellow. That trick of his of breaking in on his friends’ thoughts with an apropos remark after a quarter of an hour’s silence is really very showy and superficial. He had some analytical genius, no doubt; but he was by no means such a phenomenon as Poe appeared to imagine.”
“Have you read Gaboriau’s works?” I asked. “Does Lecoq come up to your idea of a detective?”
Sherlock Holmes sniffed sardonically. “Lecoq was a miserable bungler,” he said, in an angry voice; “he had only one thing to recommend him, and that was his energy. That book made me positively ill. The question was how to identify an unknown prisoner. I could have done it in twenty-four hours. Lecoq took six months or so. It might be made a textbook for detectives to teach them what to avoid.”