Chevallier C. Auguste Dupin was a brilliant French amateur detective.
In 1841 he investigated the case of Madame L'Espanaye and her daughter Camille L'Espanaye were killed by a monster on Rue Morgue.
In April 1898 a local prostitute Anna Coupeau was the first of prostitute murder victims and the case was re-opened. It brought the interest of Campion Bond and sent Mina Murray, and along with Allan Quatermain, to contact Dupin. Mina proposed to pose as a prostitute in order to find the English doctor she was looking for, or the ape-like murderer.
Henry Jekyll saw her and took her into his apartment, when he transformed into Hyde and went to kill her. Quatermain and Dupin showed up and tried to best the monster, shooting his ear in the process, and Quatermain managed to feed it a bottle of laudanum. Hyde lost his senses and fell through a window. The three companions apprehend Hyde's unconscious body and reached the Nautilus. Dupin was astonished at its sight. He knew about its existence but never imagined to see it alive.
Dupin was the creation of Edgar Allan Poe and appeared in "Murders in the Rue Morgue", "The Mystery of Marie Rogêt" and "The Purloined Letter" and is credited with establishing, to the greatest degree, the genre of detective fiction