Após aguir os procedimentos de G. para recuperar a carta, Dupin conclui que, de fato, o chefe polícia usou todos os recursos que estavam a seu alcance: revistas minuciosas na casa de D. e simulações de assalto a sua pessoa.
The Parisian police are exceedingly able in their way. They are persevering, ingenious, cunning, and thoroughly versed in the knowledge which their duties seem chiefly to demand. Thus, when G__ detailed to us his mode of searching the premises at the Hôtel D__, I felt entire confidence in his having made a satisfactory investigation — so far as his labours extended.
Dupin acrescenta, contudo, que faltou à polícia considerar a mente e a forma de pensar do vilão. Dado que o ministro D., poeta e matemático, teria uma inteligência peculiar, além de conhecimentos acerca dos procedimentos investigativos da polícia parisiense, ser-lhe-ia fácil prever as ações de G.
Eis o raciocínio que levou Dupin a descobrir exata localização da carta:
(…) I knew him, however, as both mathematician and poet, and my measures were adapted to his capacity, with reference to the circumstances by which he was surrounded. I knew him as a courtier, too, and as a bold intriguant. Such a man, I considered, could not fail to be aware of the ordinary policial modes of action. He could not have failed to anticipate — and events have proved that he did not fail to anticipate — the waylaying to wich he was subjected. He must have foreseen, I reflected, the secret investigation of his premises. His frequent absences from home at night, which were hailed by the Perfect as certain aids to his sucess, I regarded only as ruses, to afford opportunity for thorough search to the police, and thus the sooner to impress them with the conviction to which G__, in fact, did finally arrive — the conviction that the whole train of though (…), concerning the invariable principle of policial action in searches for articles concealed — I felt that this whole train of thought would necessarily pass though the mind of the minister. It would imperatively lead him to despise all the ordinary nooks of concealment. He could not, I reflected, be so weak as not to see that the most intricate and remote recess of his hotel would be as open as his commonest closets to the eyes, to the probles, to the gimlets, and to the microscope of the perfect. I saw, in fine, the he would be driven, as a matter of course, to simplicity, if not deliberately induced to it as a matter or choice.
Um vez que Dupin, conforme previra, encontra a carta surrupiada em local de fácil acesso no escritório do ministro D., ele se apodera dela mediante um ardil (deixando no lugar da carta da nobre dama, uma sua). Dupin recebe a recompensa paga pelo chefe de polícia o qual, mais que grato, fica estarrecido com o feito do detetetive.
Nesse conto, o vilão acaba sendo ludibriado por Dupin que planeja que ele não saiba da troca da carta até que queira fazer uso dela. Esse vilão — descrito como como cortesão inescrupuloso — não tem voz no conto.