The Murders in the Rue Morgue
"The Purloined Letter" completes Dupin's tour of different 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. French linguist Jean-Claude Milner suggests Dupin and D— are brothers, based on the final reference to Atreus and his twin brother Thyestes.