 Because none of the witnesses can agree on the language the murderer spoke , Dupin concludes they were not hearing a human voice at all . He and the narrator examine the house thoroughly ; the following day , Dupin dismisses the idea of both Le Bon 's guilt and a robbery motive , citing the fact that the gold was not taken from the room . He formulates a method by which the murderer could have entered the room and killed both women , involving an agile climb up a lightning rod and a leap to a set of open window shutters . Showing an unusual tuft of hair he recovered from the scene , and demonstrating the impossibility of the daughter being strangled by a human hand , Dupin concludes that an " <unk> @-@ <unk> " ( orangutan ) killed the women . He has placed an advertisement in the local newspaper asking if anyone has lost such an animal , and a sailor soon arrives looking for it . 
