He handed over a sheet torn from a note-book. On it was scribbled in pencil:
“£10 Reward.—The number of the cab which dropped a fare at or about the door of the Foreign Office in Charles Street at quarter to ten in the evening of May 23rd. Apply 221B, Baker Street.”
“You are confident that the thief came in a cab?”
“If not, there is no harm done. But if Mr. Phelps is correct in stating that there is no hiding-place either in the room or the corridors, then the person must have come from outside. If he came from outside on so wet a night, and yet left no trace of damp upon the linoleum, which was examined within a few minutes of his passing, then it is exceeding probable that he came in a cab. Yes, I think that we may safely deduce a cab.”
“It sounds plausible.”
“That is one of the clues of which I spoke. It may lead us to something. And then, of course, there is the bell—which is the most distinctive feature of the case. Why should the bell ring? Was it the thief who did it out of bravado? Or was it some one who was with the thief who did it in order to prevent the crime? Or was it an accident? Or was it—?” He sank back into the state of intense and silent thought from which he had emerged; but it seemed to me, accustomed as I was to his every mood, that some new possibility had dawned suddenly upon him.