 " The Murders in the Rue Morgue " also established many tropes that would become common elements in mystery fiction : the eccentric but brilliant detective , the bumbling constabulary , the first @-@ person narration by a close personal friend . Poe also portrays the police in an unsympathetic manner as a sort of foil to the detective . Poe also initiates the storytelling device where the detective announces his solution and then explains the reasoning leading up to it . It is also the first locked room mystery in detective fiction . 
