Hercule Poirot and Frank Howel Evans' Monsieur Poiret, a retired Belgian police officer living in London. A more obvious influence on the early Poirot stories is that of Arthur Conan Doyle. In "An Autobiography", Christie states, "I was still writing in the Sherlock Holmes tradition – eccentric detective, stooge assistant, with a Lestrade-type Scotland Yard detective, Inspector Japp". For his part, Conan Doyle acknowledged basing his detective stories on the model of Edgar Allan Poe's C. Auguste Dupin and his anonymous narrator, and basing his character Sherlock Holmes on Joseph Bell, who in his use of "ratiocination" prefigured Poirot's reliance on his
C. Auguste Dupin the three stories, Dupin travels through three distinct settings. In "The Murders in the Rue Morgue", he travels through city streets; in "The Mystery of Marie Rogêt", he is in the wide outdoors; in "The Purloined Letter", he is in an enclosed private space. Dupin is not actually a professional detective, and his motivations change through his appearances. In "The Murders in the Rue Morgue", he investigates the murders for his personal amusement, and to prove the innocence of a falsely accused man. He refuses a financial reward. However, in "The Purloined Letter", Dupin purposefully pursues a financial reward. While