A few minutes later came a loud knocking on the door. Simons opened it quickly, admitting a most strange old gentleman—tall and ramshackle—who was buttoned up in a chess-board inverness; whose trousers frayed out over his lustreless boots like much-defiled lace; whose coat-sleeves, protruding from the cape of his inverness, sought to make amends for the dullness of his footwear. He wore a turned-down collar and a large, black French knot. His hirsute face was tanned to the uniform hue of a coffee berry; his unkempt grey hair escaped in tufts from beneath a huge slouched hat; and his keen old eyes peered into the room through thickly pebbled spectacles.
"Dr. Lepardo!" cried Simons. "I am glad to see you, sir."
"Eh? Who's that?" said Harborne, looking out from the inner office, notebook in hand. "You should not have let anybody in, doctor."
"Excuse me, Mr. Harborne," replied Simons civilly, "but I have taken the liberty of asking Doctor Emmanuel Lepardo, whom I chanced to know was in London, to give an opinion upon the rather odd weapon with which this crime was perpetrated. He is one of the first authorities in Europe, and I thought you might welcome his assistance at this early stage of your inquiry."
"Oh," said the detective thoughtfully, "that's different. Thank you, sir," nodding to the new-comer. "I'm afraid your name isn't known to me, but if you can give us a tip or two I shall be grateful. I wish Inspector Sheffield were here. These cases are fair nightmares to me. And now it's got to murder, life won't be worth living at the Yard if we don't make an arrest."
"Yes, yes," said Dr. Lepardo, peering about him, speaking in a most peculiar, rumbling tone, and with a strong accent. "I would not have missed such a chance. Where is this dagger? I have just returned from the Izamal temples of Yucatan. I have brought some fine specimens to Europe. Obsidian knives. Sacrificial. Beautiful."
He shuffled jerkily into the private office, seemed to grasp its every detail in one comprehensive, peering glance, and pounced upon the dagger with a hoarse exclamation. The Scotland Yard man watched him with curiosity, and Julius Rohscheimer, in the open door, followed his movements with a newly awakened interest.
"True Damascus!" he muttered, running a long finger up the blade. "Hilt, Persian—not Kultwork—Persian. Yes. Can I pull it out? Yes? Damascened to within three inches. Very early."
He turned to the detective, dagger in hand.
"This is a Turkish yataghan."