In the story, the expert investigator has rejected the obsolete conventional police methods. Dupin acknowledges that traditional law enforcement measures are judiciously used during an investigation by the police. But, these measures are unoriginal and do not yield results. The Parisian police are more interested in the specifics of the case and have lost objectivity. “The Murders in the Rue Morgue” had demonstrated the inefficacy of the police to look beyond the gruesome double homicide. Dupin is objective, cold and skeptical. For him, the crime scene is a site of calculation.
The Purloined Letter remarkably illustrates Dupin’s adventurous zeal. By risking his own self, he retrieves the letter. The Paris police were cautious of Minister D——, an influential official, Dupin remained indifferent to the social station of the purloiner. He is extraordinarily patient in repaying the slight. His mode of investigation thrives on intuition and personal cunning, which cannot be institutionalized in a traditional police force.