The Purloined Letter

"The Purloined Letter" begins with Dupin's friend, the narrator, visiting him at his home. The Prefect of the Parisian police interrupts the investigation. The Prefect seeks Dupin's assistance in locating a stolen letter. He informs Dupin that the letter contains sensitive information. And potentially has blackmail material against a prominent societal figure.

The Prefect explains that the letter was stolen by Minister D—, who concealed it in plain sight. Minister D– placed it among his correspondence. Despite conducting thorough searches, the police have been unable to find it. Dupin becomes intrigued by the case and offers his help.

Dupin deduces Minister D—, expecting the police to search for the purloined letter, would have hidden it where it was obvious. He determines the letter is still in Minister D—'s possession and that he is using it against potential exposure.

Dupin and the narrator devise a plan to recover the letter. Dupin disguises himself and visits Minister D—'s apartment, where he successfully switches the letter with a duplicate. The police are to make an official search. But they are unable to locate the real letter, as it is now in the hands of Dupin.

With the letter safely retrieved, Dupin reveals his methods to the Prefect. He explains how he employed psychology and careful observation to solve the case. Dupin demonstrates that the police had overlooked the key element of the case. They assume the thief would hide the purloined letter in an obscure location rather than in plain sight.