Mystery
It was tough for us to let go of the genre of "Horror" for "The Murders in the Rue Morgue." After all, Poe is the author of " The Cask of Amontillado " (where someone gets buried alive) and "The Tell-Tale Heart" (which features a murder victim under the floorboards), and happens to be the master at writing stories to freeze the blood. "The Murders in the Rue Morgue" is a good candidate for horror because of the real disgustingness of the murders – a lady's head does falls off. Pretty horrifying. But while all of these details make the murders terrifying to the neighborhood, what puts this story in the genre of mystery is the matter-of-fact way that the story lays out its grossest elements like a checklist. The reader doesn't have a lot of emotional investment in what's going on. In fact, the only thing that's important is surveying all the clues the story gives us and trying to solve the matter along with genius detective, Dupin. This story is effectively a puzzle, both for its protagonist and its reader, putting it squarely in the genre of "Mystery."