I tapped loudly at the door, at the same moment summoning all my self-possession. I was about to secure one of the most cunning and clever criminals on earth.

There was no answer. Yet I distinctly heard some one within the room.

Again I knocked loudly.

Then I heard footsteps advancing to the door, which was thrown open, and a chambermaid stood there.

"I'm sorry, sir," she said apologetically.

I drew back in dismay.

"Is Mr. Vernon in here?" I asked breathlessly.

"Mr. Vernon—the gentleman in this room, sir?"

"Yes. He has come up here, I know."