Final answer:
The student's question mixes up characters from different literary works. In 'The Purloined Letter' by Poe, the Prefect conducts a thorough search for a letter, while Dupin devises his own method to locate it.
Step-by-step explanation:
The question refers to a narrative within The Purloined Letter, a short story by Edgar Allan Poe, where various characters discuss the investigative strategies regarding a letter of political importance. There is no Count or character named Danglars in this narrative; it appears there might be a confusion with The Count of Monte Cristo by Alexandre Dumas, where a character named Danglars features prominently.
In Poe's story, however, it is Monsieur G-, the Prefect of the Parisian police, who speaks of conducting a thorough search of the premises. Dupin, a private consultant in matters of mystery, suggests investigating beyond conventional police methods, knowing that the Minister D— has likely anticipated and countered typical search strategies. The narrative unfolds with Dupin ultimately uncovering the whereabouts of the hidden letter through his own cunning means.