They moved cautiously to the connecting-door of the room in the rear.  The lamplight partly illuminated it, revealing it as a bedroom.

Bedclothes trailed to the floor, which also was littered with dingy masculine apparel flung about at random.  Pockets of trousers and of coats had been turned inside out, in what apparently had been a hasty and frantic search.

The remainder of the room was in disorder, too; underwear had been pulled from dresser and bureau; the built-in wardrobe doors swung ajar and the clothing lay scattered about, every pocket turned inside out.

“For heaven’s sake,” muttered Vaux, “what do you suppose this means?”

“Look!” she whispered, clutching his arm and pointing to the fireplace at their feet.

On the white-tiled hearth in front of the unlighted gas-logs lay the stump of a cigar.

From it curled a thin thread of smoke.

They stared at the smoking stub on the hearth, gazed fearfully around the dimly lighted bedroom, and peered into the dark dining-room beyond.

Suddenly Miss Erith’s hand tightened on his sleeve.

“Hark!” she motioned.

He heard it, too—­a scuffling noise of heavy feet behind a closed door somewhere beyond the darkened dining-room.

“There’s somebody in the kitchenette!” she whispered.

Vaux produced his pistol; they stole forward into the dining-room; halted by the table.

“Flash that door,” he said in a low voice.

Her electric torch played over the closed kitchen door for an instant, then, at a whispered word from him, she shut it off and the dining-room was plunged again into darkness.

And then, before Vaux or Miss Erith had concluded what next was to be done, the kitchen door opened; and, against the dangling lighted bulb within, loomed a burly figure wearing hat and overcoat and a big bass voice rumbled through the apartment: 

“All right, all right, keep your shirt on and I’ll get your coat and vest for you—­”

Then Miss Erith flashed her torch full in the man’s face, blinding him.  And Vaux covered him with levelled pistol.

Even then the man made a swift motion toward his pocket, but at Vaux’s briskly cheerful warning he checked himself and sullenly and very slowly raised both empty hands.

“All right, all right,” he grumbled.  “It’s on me this time.  Go on; what’s the idea?”

“W-well, upon my word!” stammered Vaux, “it’s Cassidy!”

“F’r the love o’ God,” growled Cassidy, “is that you, Mr. Vaux!” He lowered his arms sheepishly, reached out and switched on the ceiling light over the dining-room table.  “Well, f’r—­” he began; and, seeing Miss Erith, subsided.

“What are you doing here?” demanded Vaux, disgusted with this glaring example of interference from another service.

“What am I doing?” repeated Cassidy with a sarcastic glance at Miss Erith.  “Faith, I’m pinching a German gentleman we’ve been watching these three months and more.  Is that what you’re up to, too?”