“The Murders in the Rue Morgue” also relies on the role of the narrator as Dupin’s friend. Poe chooses not to use Dupin as a narrator in order to provide a sense of detachment from the workings of the mind that the story describes. The narrator’s role as a foil enhances Dupin as the detective hero. The narrator admires Dupin and prompts him to elicit his analysis, which always astounds the narrator. He allows himself to be outwitted by Dupin, thereby demonstrating that Dupin thinks one step ahead of both the police and the average reader. Accompanying Dupin to the crime scene, the narrator ostensibly witnesses the same evidence, but needs the explanations of his friend in order to see the true nature of the evidence and to understand its part in the larger puzzle.
Part of Dupin’s brilliance is his ability to separate himself from the emotional atrocity of the crime scene. The police become distracted by the sheer inhuman cruelty of the scene, but Dupin is able to look beyond the violence and coolly investigate the small details that otherwise go unnoticed. The decapitation of Madame L’Espanaye is just one ghastly example that, according to Dupin, draws the police away from solving the crime. For all of Dupin’s rationality and cunning, though, the actual explanation of the crime is, by all accounts, ridiculous—the Ourang-Outang did it. It is difficult to discern whether he intended this solution to be humourous. If the story is to be construed in some way as a joke—the detective story was too young at this time to be parodied—it is a joke told with the straightest of faces. Poe’s tendency to exaggerate gets the better of him in his effort to illustrate the analytic contrasts between Dupin and the Paris police. One can argue that Dupin’s brilliance is ultimately overshadowed by the need to import a wild animal into the solution to the crime. Dupin gets the case right, but Poe may, in fact, go too far in exaggerating the power of his protagonist’s reasoning.