I stepped over to the door, where a constable stood on duty.
"You observed a tall Eastern gentleman in the room a while ago, officer?"
"I did, sir."
"How long is he gone?"
The man started and began to peer about anxiously.
"That's a funny thing, sir," he said. "I was keeping my eyes specially upon him. I noticed him hovering around while Mr. Mostyn was speaking; but although I could have sworn he hadn't passed out, he's gone!"
"You didn't notice his departure, then?"
"I'm sorry to say I didn't, sir."
The man clearly was perplexed, but I found small matter for wonder in the episode. I had more than suspected the stranger to be a spy of Hassan's, and members of that strange company were elusive as will-o'-the-wisps.
Bristol, at the far end of the room, was signalling to me. I walked back and joined him.
"Come over here," he said, in a low voice, "and pretend to examine these things."
He glanced significantly to his left. Following the glance, my eyes fell upon the lean American; he was peering into the receptacle which held the holy slipper.
Bristol led me across the room, and we both faced the wall and bent over a glass case. Some yellow newspaper cuttings describing its contents hung above it, and these we pretended to read.
"Did you notice that man I glanced at?"
"Yes."
"Well, that's Earl Dexter, the first crook in America! Ssh! Only goes in on very big things. We had word at the Yard he was in town; but we can't touch him - we can only keep our eyes on him. He usually travels openly and in his own name, but this time he seems to have slipped over quietly. He always dresses the same and has just given me 'good day!' They call him The Stetson Man. We heard this morning that he had booked two first-class sailings in the Oceanic, leaving for New York three weeks hence. Now, Mr. Cavanagh, what is his game?"
"It has occurred to me before, Bristol," I replied, "and you may remember that I mentioned the idea to you, that there might be a third party interested in the slipper. Why shouldn't Earl Dexter be that third party?"
"Because he isn't a fool," rapped Bristol shortly. "Earl Dexter isn't a man to gather up trouble for himself. More likely if his visit has anything really to do with the slipper he's retained by Hassan and Company. Museum-breaking may be a bit out of the line of Hashishin!"
This latter suggestion dovetailed with my own ideas, and oddly enough there was something positively wholesome in the notion of the straightforward crookedness of a mere swell cracksman.
Then happened a singular thing, and one that effectually concluded our whispered colloquy. From the top end of the room, beyond the case containing the slipper, one of the yellow blinds came down with a run.
Bristol turned in a flash. It was not a remarkable accident, and might portend no more than a loose cord; but when, having walked rapidly up the room, we stood before the lowered blind, it appeared that this was no accident at all.
Some four feet from the bottom of the blind (or five feet from the floor) a piece of linen a foot square had been neatly slashed out!
I glanced around the room. Several fashionably dressed visitors were looking idly in our direction, but I could fasten upon no one of them as a likely perpetrator.
Bristol stared at me in perplexity.
"Who on earth did it," he muttered, "and what the blazes for?"