"One moment," he said, and opened his bag. "Here"--pouring out a draught into a little glass--"drink this. And favour me with two minutes' conversation before the police arrive." Rohscheimer drank it off and followed the movements of the doctor, who stepped to the telephone and called up a Gerrard number. "Doctor John Simons speaking," he said presently. "Come _at once_ to Moorgate Place, Moorgate Street. Murder been committed by--Severac Bablon. Most peculiar weapon used. The police, no doubt, would value an expert opinion. You _must_ be here within ten minutes." The arrival of a couple of constables frustrated whatever object Dr. Simons had had in detaining Mr. Rohscheimer, but the doctor lingered on, evidently awaiting whoever he had spoken to on the telephone. The police ascertained from Rohscheimer that he had held an interest in the "Douglas Graham" business, that this business was of an usurious character, that the dead man's real name was Paul Gottschalk, and that he, Rohscheimer, found the outer door fastened when he arrived at about seven o'clock, opened it with a key which he held, and saw Gottschalk as they saw him now. The office was in darkness. Apparently, valuables had been taken from the safe--which was open. The staff usually left at six. This was the point reached when Detective Harborne put in an appearance and, with professional nonchalance, took over the investigation. Dr. Simons glanced at his watch and impatiently strode up and down the outside office. 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."