"Do you mean to infer that the old man we saw enter the house was the Count Reiffenburg?" I asked, aghast. "That is my belief, sir," said the man; "and I feel certain that if I were allowed to search his bedroom, I should find my suspicions corroborated." "But what possible reason could he have for masquerading as a pauper outcast, and who let him in?" "As to his reason, sir, I can hazard no sort of guess," he continued. "But it was the lady herself who let him in." "How on earth do you know that?" "By a process of simple reasoning, sir. Did you happen to notice that, when we returned to the hall after our search of the first section of the house, the gentleman carried a book in his hand?" "Now that you mention the fact I _do_ remember it," I answered. "But what has the book to do with it?" "A great deal," he answered. "You may not be aware of the fact, but there's a small sitting-room near that side door--a tiny place where the housekeeper does her accounts. The book, when we first searched the room, was lying upon the table." "May not the housekeeper have been reading it before she went to bed?" "The housekeeper is an Englishwoman, sir, and not very well educated. I should call it remarkable if she knew Italian, and little short of marvellous if she read Dante in the original. Now, sir, when Count Reiffenburg entered the lady's boudoir, he brought that book with him and placed it on one of the tables. He wouldn't have done that if it had been the property of the housekeeper, would he? No, sir! Count Reiffenburg was out, and the young lady, who is his cousin, I think I understood you to say, sir, sat up for him in order to be near the door. That's the way I read the riddle." "And I must confess that you have a certain amount of probability on your side," I answered. "At the same time, if I were you, I should say nothing about the discovery. It can serve no good purpose to bruit it abroad. Do you think the two policemen noticed anything of the kind?" The detective gave a scornful little laugh. "I don't think you need have much fear on that score, sir," he answered. "I doubt very much whether the man who went round with me noticed the book at all. His theory was that the fellow we saw enter was one of the servants who had been out late, and not a burglar at all."