When Dupin is first written about he has gone from an illustrious family to being
"reduced to such poverty that the energy of his character succumbed beneath it." -- Edgar Allen Poe
So much so that he ends up making a friend who rooms with him. As roommates Dupin's friend notices things about his observances and his skills became quite useful when Madame L'Espanaye and her daughter Camille were brutally murdered by of all things an Orangutan. The suspect for the murder however was a man, Adolphe Le Bon who was arrested and imprisoned. Dupin is not only able to find out that the murder was done by an orangutan but he was also able to get the owner of the orangutan and eye witness to the murders to confess to what he knew. This story has been recounted over and over again in comics.
Dupin is considered the first detective character first appearing in Edgar Allan Poe's The Murders in the Rue Morgue. The Murders in the Rue Morgue is such a popular and influential story that it is Dupin and the case is referenced in the first Sherlock Holmes novel A Study In Scarlet. Dupin even has a partner like Watson who rooms with him at the beginning of their friendship due to financial constraints. This is also seen in A Study In Scarlet. Unfortunately, the narrator is unmentioned as in many Poe stories.
Major Story Arcs
In the League of Extraordinary Gentlemen Dupin has become a renown detective and retired by the year 1898. At that time he comes out of retirement to help Wilhelmina Murray find a mysterious Doctor who turns out to be Dr. Jekyll. The three manage to capture Hyde and leaving Dupin to his retirement in Paris, France.