That Sin Sin Wa thought him to be still unconscious he did not believe.  He was confident that his tactics had deceived the Jewess, but he entertained an almost superstitious respect for the cleverness of the Chinaman.  The trick with the ball of leaf opium was painfully fresh in his memory.

Kerry, in common with many members of the Criminal Investigation Department, rarely carried firearms.  He was a man with a profound belief in his bare hands—­aided when necessary by his agile feet.  At the moment that Sin Sin Wa had checked the woman’s murderous and half insane outburst Kerry had been contemplating attack.  The sudden change of language on the part of the Chinaman had arrested him in the act; and, realizing that he was listening to a confession which placed the hangman’s rope about the neck of Mrs. Sin, he lay still and wondered.

Why had Sin Sin Wa forced his wife to betray herself?  To clear Mareno?  To clear Mrs. Irvin—­or to save his own skin?

It was a frightful puzzle for Kerry.  Then—­where was Kazmah?  That Mrs. Irvin, probably in a drugged condition, lay somewhere in that mysterious inner room Kerry felt fairly sure.  His maltreated skull was humming like a bee-hive and aching intensely, but the man was tough as men are made, and he could not only think clearly, but was capable of swift and dangerous action.

He believed that he could tackle the Chinaman with fair prospects of success; and women, however murderous, he habitually disregarded as adversaries.  But the mummy-like, deceptive Sam Tuk was not negligible, and Kazmah remained an unknown quantity.

From under that protective arm, cast across his face, Kerry’s fierce eyes peered out across the dirty floor.  Then quickly he shut his eyes again.

Sin Sin Wa, crooning his strange song, came in carrying a coil of rope —­and a Mauser pistol!

“P’licemanee gotchee catchee sleepee,” he murmured, “or maybe he catchee die!”

He tossed the rope to his wife, who stood silent tapping the floor with one slim restless foot.

“Number one top-side tie up,” he crooned.  “Sin Sin Wa watchee withum gun!”

Kerry lay like a dead man; for in the Chinaman’s voice were menace and warning.

CHAPTER XXXIX

THE EMPTY WHARF

The suspected area of Limehouse was closely invested as any fortress of old when Seton Pasha once more found himself approaching that painfully familiar neighborhood.  He had spoken to several pickets, and had gathered no news of interest, except that none of them had seen Chief Inspector Kerry since some time shortly before dusk.  Seton, newly from more genial climes, shivered as he contemplated the misty, rain-swept streets, deserted and but dimly lighted by an occasional lamp.  The hooting of a steam siren on the river seemed to be in harmony with the prevailing gloom, and the most confirmed optimist must have suffered depression amid those surroundings.