Mysterious pots and pans, strainers, wooden vessels, and testing instruments were about.  The odour of opium in the manufacture was unmistakable, for smoking opium is different from the medicinal drug.  There it appeared the supplies of thousands of smokers all over the country were stored and prepared.  In a corner a mass of the finished product lay weltering in a basin like treacle.  In another corner was the apparatus for remaking yen-shee or once-smoked opium.  This I felt was at last the home of the “dope trust,” as O’Connor had once called it, the secret realm of a real opium king, the American end of the rich Shanghai syndicate.

A door opened and there stood a Chinaman, stoical, secretive, indifferent, with all the Oriental cunning and cruelty hall-marked on his face.  Yet there was a fascination and air of Eastern culture about him in spite of that strange and typical Oriental depth of intrigue and cunning that shone through, great characteristics of the East.

No one said a word as Kennedy continued to ransack the place.  At last under a rubbish heap he found a revolver wrapped up loosely in an old sweater.  Quickly, under the bright light, Craig drew Clendenin’s pistol, fitted a cartridge into it and fired at the wall.  Again into the second gun he fitted another and a second shot rang out.

Out of his pocket came next the small magnifying glass and two unmounted microphotographs.  He bent down over the exploded shells.

“There it is,” cried Craig scarcely able to restrain himself with the keenness of his chase, “there it is—­the mark like an ‘L.’  This cartridge bears the one mark, distinct, not possible to have been made by any other pistol in the world.  None of the Hep Sings, all with the same make of weapons, none of the gunmen in their employ, could duplicate that mark.”

“Some bullets,” reported a policeman who had been rummaging further in the rubbish.

“Be careful, man,” cautioned Craig.  “They are doped.  Lay them down.  Yes, this is the same gun that fired the shot at Bertha Curtis and Nichi Moto—­fired narcotic bullets in order to stop any one who interfered with the opium smuggling, without killing the victim.”

“What’s the matter?” asked O’Connor, arriving breathless from the gambling room after hearing the shots.  The Chinaman stood, still silent, impassive.  At sight of him O’Connor gasped out, “Chin Jung!”

“Real tong leader,” added Craig, “and the murderer of the white girl to whom he was engaged.  This is the goggled chauffeur of the red car that met the smuggling boat, and in which Bertha Curtis rode, unsuspecting, to her death.”

“And Clendenin?” asked Walker Curtis, not comprehending.

“A tool—­poor wretch.  So keen had the hunt for him become that he had to hide in the only safe place, with the coolies of his employer.  He must have been in such abject terror that he has almost smoked himself to death.”