"Knox," whispered Harley in my ear, "when that woman comes down, follow her! I'm afraid you will bungle the business, and I would not ask you to attempt it if big things were not at stake. Return here; I shall wait."

As a matter of fact, his sudden request had positively astounded me, but ere I had time for any reply a door suddenly banged open above and a respectable-looking woman, who might have been some kind of upper servant, came quickly down the stairs. An expression of intense indignation rested upon her face, and without seeming to notice our presence she brushed past us and went out into the street.

"Off you go, Knox!" said Harley.

Seeing myself committed to an unpleasant business, I slipped out of the doorway and detected the woman five or six yards away hurrying in the direction of Piccadilly. I had no difficulty in following her, for she was evidently unsuspicious of my presence, and when presently she mounted a westward-bound 'bus I did likewise, but while she got inside I went on top, and occupied a seat on the near side whence I could observe anyone leaving the vehicle.

If I had not known Paul Harley so well I should have counted the whole business a ridiculous farce, but recognizing that something underlay these seemingly trivial and disconnected episodes, I lighted a cigarette and resigned myself to circ.u.mstance.

At Hyde Park Corner I saw the woman descending, and when presently she walked up Hamilton Place I was not far behind her. At the door of an imposing mansion she stopped, and in response to a ring of the bell the door was opened by a footman, and the woman hurried in. Evidently she was an inmate of the establishment; and conceiving that my duty was done when I had noted the number of the house, I retraced my steps to the corner; and, hailing a taxicab, returned to the Cafe Dame.

On inquiring of the same waiter whom Harley had accosted whether my friend was there:

"I think a gentleman is upstairs with Mr. Meyer," said the man.

"In his office?"

"Yes, sir."

Thereupon I mounted the stairs and before a half-open door paused.

Harley's voice was audible within, and therefore I knocked and entered.

I discovered Harley standing by an American desk. Beside him in a revolving chair which, with the desk, const.i.tuted the princ.i.p.al furniture of a tiny office, sat a man in a dress-suit which had palpably not been made for him. He had a sullen and suspiciously Teutonic cast of countenance, and he was engaged in a voluble but hardly intelligible speech as I entered.

"Ha, Knox!" said Harley, glancing over his shoulder, "did you manage?"

"Yes," I replied.

Harley nodded shortly and turned again to the man in the chair.

"I am sorry to give you so much trouble, Mr. Meyer," he said, "but I should like my friend here to see the room above."

At this moment my attention was attracted by a singular object which lay upon the desk amongst a litter of bills and accounts. This was a piece of rusty iron bar somewhat less than three feet in length, and which once had been painted green.

"You are looking at this tragic fragment, Knox," said Harley, taking up the bar. "Of course"--he shrugged his shoulders--"it explains the whole unfortunate occurrence. You see there was a flaw in the metal at this end, here"--he indicated the spot--"and the other end had evidently worn loose in its socket."

"But I don't understand."

"It will all be made clear at the inquest, no doubt. A most unfortunate thing for you, Mr. Meyer."

"Most unfortunate," declared the proprietor of the restaurant, extending his thick hands pathetically. "Most ruinous to my business."

"We will go upstairs now," said Harley. "You will kindly lead the way, Mr. Meyer, and the whole thing will be quite clear to you, Knox."

As the proprietor walked out of the office and upstairs to the second floor Harley whispered in my ear:

"Where did she go?"

"No. ---- Hamilton Place," I replied in an undertone.

"Good G.o.d!" muttered my friend, and clutched my arm so tightly that I winced. "Good G.o.d! The master touch, Knox! This crime was the work of a genius--of a genius with slightly, very slightly, oblique eyes."

Opening a door on the second landing, Mr. Meyer admitted us to a small supper-room. Its furniture consisted of a round dining table, several chairs, a couch, and very little else. I observed, however, that the furniture, carpet, and a few other appointments were of a character much more elegant than those of the public room below. A window which overlooked the street was open, so that the plush curtains which had been drawn aside moved slightly to and fro in the draught.

"The window of the tragedy, Knox," explained Harley.

He crossed the room.

"If you will stand here beside me you will see the gap in the railing caused by the breaking away of the fragment which now lies on Mr.

Meyer's desk. Some few yards to the left in the street below is where the a.s.sault took place, of which we have heard, and the unfortunate Mr. De Lana, who was dining here alone--an eccentric custom of his--naturally ran to the window upon hearing the disturbance and leaned out, supporting his weight upon the railing. The rail collapsed, and--we know the rest."

"It will ruin me," groaned Meyer; "it will give bad repute to my establishment."

"I fear it will," agreed Harley sympathetically, "unless we can manage to clear up one or two little difficulties which I have observed.

For instance"--he tapped the proprietor on the shoulder confidentially--"have you any idea, any hazy idea, of the ident.i.ty of the woman who was dining here with Mr. De Lana on Wednesday night?"

The effect of this simple inquiry upon the proprietor was phenomenal.

His fat yellow face a.s.sumed a sort of leaden hue, and his already prominent eyes protruded abnormally. He licked his lips.

"I tell you--already I tell you," he muttered, "that Mr. De Lana he engage this room every Wednesday and sometimes also Friday, and dine here by himself."

"And I tell you," said Harley sweetly, "that you are an inspired liar.

You smuggled her out by the side entrance after the accident."

"The side entrance?" muttered Meyer. "The side entrance?"

"Exactly; the side entrance. There is something else which I must ask you to tell me. Who had engaged this room on Tuesday night, the night before the accident?"

The proprietor's expression remained uncomprehending, and:

"A gentleman," he said. "I never see him before."

"Another solitary diner?" suggested Harley.

"Yes, he is alone all the evening waiting for a friend who does not arrive."

"Ah," mused Harley--"alone all the evening, was he? And his friend disappointed him. May I suggest that he was a dark man? Gray at the temples, having a dark beard and moustache, and a very tanned face? His eyes slanted slightly upward?"

"Yes! yes!" cried Meyer, and his astonishment was patently unfeigned.

"It is a friend of yours?"

"A friend of mine, yes," said Harley absently, but his expression was very grim. "What time did he finally leave?"

"He waited until after eleven o'clock. The dinner is spoilt. He pays, but does not complain."

"No," said Harley musingly, "he had nothing to complain about. One more question, my friend. When the lady escaped hurriedly on Wednesday night, what was it that she left behind and what price are you trying to extort from her for returning it?"

At that the man collapsed entirely.