“I do _not_ know it,” said Dupin. “I am not _sure_ of it. Here, however, is a small piece of ribbon, which has evidently, from its form, and from its greasy appearance, been used in tying the hair in one of those long _queues_ of which sailors are so fond. Moreover, this knot is one which few besides sailors can tie, and is peculiar to the Maltese. I picked the ribbon up at the foot of the lightning-rod. It could not have belonged to either of the deceased. Now if, after all, I am wrong in my induction from this ribbon, that the Frenchman was a sailor belonging to a Maltese vessel, still I can have done no harm in stating what I did in the advertisement. If I am in error he will merely suppose that I have been misled by some circumstance into which he will not take the trouble to inquire. But if I am right—a great point is gained. Cognizant of the murder, although not guilty, the Frenchman will naturally hesitate about replying to the advertisement—about demanding the Ourang-Outang. He will reason thus:—‘I am innocent; I am poor; my Ourang-Outang is of great value—to one in my circumstances a fortune of itself—why should I lose it through idle apprehensions of danger? Here it is within my grasp. It was found in the Bois de Boulogne—at a vast distance from the scene of that butchery. How can it ever be suspected that a brute beast should have done the deed? The police are at fault—they have failed to procure the slightest clew. Should they even trace the animal, it would be impossible to prove me cognizant of the murder, or to implicate me in guilt on account of that cognizance. Above all, _I am known_. The advertiser designates me as the possessor of the beast. I am not sure to what limit his knowledge may extend. Should I avoid claiming a property of so great a value, which it is known that I possess, I will render the animal at least, liable to suspicion. It is not my policy to attract attention either to myself or to the beast. I will answer the advertisement—get the Ourang-Outang, and keep it close until this matter has blown over.’” At this moment we heard a step upon the stairs. “Be ready,” said Dupin, “with your pistols, but neither show them nor use them until at a signal from myself.” The front door of the house had been left open, and the visiter had entered without ringing or rapping, and advanced several steps upon the staircase. Now, however, he seemed to hesitate. Presently we heard him descending. Dupin was moving quickly to the door, when we again heard him coming up. He did not turn back a second time, but stepped up quickly, and rapped at the door of our chamber. “Come in,” said Dupin, in a cheerful and hearty tone.