How does C. Auguste Dupin solve crimes in “The Murders in the Rue Morgue”?

In the short story "The Murders in the Rue Morgue," C. Auguste Dupin solves the seemingly impossible crime by employing a method he calls "ratiocination," which relies on rigorous logic and analysis.12

Rather than relying on traditional police methods, the amateur detective examines the crime scene with extreme attention to detail. By interpreting clues that the authorities overlook—specifically the fact that the apartment was sealed from the inside—Dupin deduces that the perpetrator was not a human, but an escaped orangutan.1

This approach established the archetype of the brilliant, eccentric investigator who solves mysteries through intellectual deduction rather than physical force. Dupin’s reliance on observation and reasoning served as the foundational model for later iconic literary detectives, including Sherlock Holmes and Hercule Poirot.12