“He may have been seen.”

“He undoubtedly was seen by two or three people, but no one thought anything of seeing a man leave the house at that hour.  It was very cold, the snow was falling thickly, and as he wore a muffler round the lower part of his face, those who saw him would not undertake to know him again.”

“That man was never seen nor heard of again?” Polly asked.

“He has disappeared off the face of the earth.  The police are searching for him, and perhaps some day they will find him—­then society will be rid of one of the most ingenious men of the age.”

CHAPTER XXXVI

THE END

He had paused, absorbed in meditation.  The young girl also was silent.  Some memory too vague as yet to take a definite form was persistently haunting her—­one thought was hammering away in her brain, and playing havoc with her nerves.  That thought was the inexplicable feeling within her that there was something in connection with that hideous crime which she ought to recollect, something which—­if she could only remember what it was—­would give her the clue to the tragic mystery, and for once ensure her triumph over this self-conceited and sarcastic scarecrow in the corner.

He was watching her through his great bone-rimmed spectacles, and she could see the knuckles of his bony hands, just above the top of the table, fidgeting, fidgeting, fidgeting, till she wondered if there existed another set of fingers in the world which could undo the knots his lean ones made in that tiresome piece of string.

Then suddenly—­a propos of nothing, Polly remembered—­the whole thing stood before her, short and clear like a vivid flash of lightning:—­Mrs. Owen lying dead in the snow beside her open window; one of them with a broken sash-line, tied up most scientifically with a piece of string.  She remembered the talk there had been at the time about this improvised sash-line.

That was after young Greenhill had been discharged, and the question of suicide had been voted an impossibility.

Polly remembered that in the illustrated papers photographs appeared of this wonderfully knotted piece of string, so contrived that the weight of the frame could but tighten the knots, and thus keep the window open.  She remembered that people deduced many things from that improvised sash-line, chief among these deductions being that the murderer was a sailor—­so wonderful, so complicated, so numerous were the knots which secured that window-frame.

But Polly knew better.  In her mind’s eye she saw those fingers, rendered doubly nervous by the fearful cerebral excitement, grasping at first mechanically, even thoughtlessly, a bit of twine with which to secure the window; then the ruling habit strongest through all, the girl could see it; the lean and ingenious fingers fidgeting, fidgeting with that piece of string, tying knot after knot, more wonderful, more complicated, than any she had yet witnessed.