"Who was it?" I asked eagerly. "Do you suspect?"
He made no answer but took from his pocket the object which had fallen from the divan. It was a heavy gold ring, evidently a man's. He looked at it critically and then held it out to me.
"Do you know whose it is?" he asked low.
Before I could take it from him he hastily slipped it back into his pocket and leaning closer, said in my ear, "Don't make a sound, but look at the safe door. Then turn back and listen to me as though nothing were amiss."
I was sitting around the corner from the head of the table with my chair turned slightly in McKelvie's direction so that my back was partly toward the safe. At his words I turned and looked at the safe door, expecting I know not what, and to my amazement I saw that the knob of the dial was turning silently and apparently of itself!
There was only one explanation. Someone was opening the door of the safe from the inside, somebody who knew the combination which McKelvie had used! And yet how could anyone have cognizance of the six letters McKelvie had picked out to close the safe. For this was no attempt such as Jenkins had made, no adept manipulation, since the dial was turning with precision, as though the hand that twirled it knew exactly how to spin it.
McKelvie's foot on mine recalled the remainder of his injunction, and turning back, I held out my hand for the ring. His lips formed the word, "No," and his eyes directed me to what he held in his hand. It was Lee Darwin's stick-pin.
"I thought there was someone in the room when we entered," he said in a clear voice, "but since you say you did not see the light, why I must have been mistaken. The case is getting on my nerves, and nerves are queer things when they begin to jump. I've been working too hard, and it's time I took a vacation."
He paused, and I had an uncomfortable feeling that whoever was in the safe had succeeded in opening it and was gazing at us from behind the shelter of the door. I shuddered as I realized the intensity of those unseen eyes which held me riveted to my chair. I longed to turn around and look and so break the spell, but McKelvie's glance on mine forbade it.
"I'm convinced that Lee killed his uncle," he continued. "The stick-pin proves his presence, and doubtless he had knowledge of the entrance. There is nothing more to be learned from this study. My work from now on must be conducted outside. As I said, I've got a man in the South and until he picks up Lee's trail there is nothing more to be done."