“And what did he say?”

“Oh”—­she shrugged her shoulders—­“he just smiled and told me not to worry.”

“And that was the last you heard about the matter?”

“Yes, until you told me he was dead.”

Again he questioned the dark eyes and again was baffled.  He felt tempted, and not for the first time, to throw up the case.  After all, it rested upon very slender data—­the mysterious death of a Chinaman whose history was unknown and the story of a crook whose word was worth nothing.

Finally he asked himself, as he had asked himself before, what did it matter?  If old Huang Chow had disposed of these people in some strange manner, they had sought to rob him.  The morality of the case was complicated and obscure, and more and more he was falling under the spell of Lala’s dark eyes.

But always it was his professional pride which came to the rescue.  Murder had been done, whether justifiably or otherwise, and to him had been entrusted the discovery of the murderer.  It seemed that failure was to be his lot, for if Lala knew anything she was a most consummate actress, and if she did not, his last hope of information was gone.

He would have liked nothing better than to be rid of the affair, provided he could throw up the case with a clear conscience.  But when presently he parted from the attractive Eurasian, and watched her slim figure as, turning, she waved her hand and disappeared round a corner, he knew that rest was not for him.

He had discovered the emporium of a Shadwell live-stock dealer with whom Ah Fu had a standing order for newly fledged birds of all descriptions.  Purchases apparently were always made after dusk, and Ah Fu with his birdcage was due that evening.

A scheme having suggested itself to Durham, he now proceeded to put it into execution, so that when dusk came, and Ah Fu, carrying an empty birdcage, set out from the house of Huang Chow, a very dirty-looking loafer passed the corner of the street at about the time that the Chinaman came slinking out.

Durham had mentally calculated that Ah Fu would be gone about half an hour upon his mysterious errand, but the Chinaman travelled faster than he had calculated.

Just as he was about to climb up once more on to the sloping roof, he heard the pattering footsteps returning to the courtyard, although rather less than twenty minutes had elapsed since the man had set out.

Durham darted round the corner and waited until he heard the door closed; then, returning, he scrambled up on to the roof, creeping forward until he was lying looking down through the skylight into the darkened room below.

For ten minutes or more he waited, until he began to feel cramped and uncomfortable.  Then that happened which he had hoped and anticipated would happen.  The place beneath became illuminated, not fully, by means of the hanging lamps, but dimly so that distorted shadows were cast about the floor.  Someone had entered carrying a lantern.