came a slight, almost sibilant sound, which I took to be the gentle closing of a distant door.
Whilst I was still wondering if I had really heard this sound or merely imagined it:
“Who goes there?” came sharply in Harley’s voice.
I heard a faint click, and knew that he had shone the light of an electric torch down into the hall.
I hesitated no longer, but ran along to join him. As I came to the head of the main staircase, however, I saw him crossing the hall below. He was making in the direction of the door which shut off the servants’ quarters. Here he paused, and I saw him trying the handle. Evidently the door was locked, for he turned and swept the white ray all about the place. He tried several other doors, but found them all to be locked, for presently he came upstairs again, smiling grimly when he saw me there awaiting him.
“Did you hear it, Knox?” he said.
“A sound like the closing of a door?”
Paul Harley nodded.
“It was the closing of a door,” he replied; “but before that I had distinctly heard a stair creak. Someone crossed the hall then, Knox. Yet, as you perceive for yourself, it affords no hiding-place.”
His glance met and challenged mine.
“The Colonel’s visitor has left him,” he murmured. “Unless something quite unforeseen occurs, I shall throw up the case to-morrow.”
