"I've called quite by chance and upon business," I explained. "I'm a motor-car engineer, and I live in Chiswick. My name is Holford." "Mine's Langton--Leonard Langton," he answered. Then, after a second's hesitation, he added, "Ethelwynn--Miss Greer--is to become my wife. That's why I'm surprised that she hasn't kept the appointment I made." I was silent. What if I told him of the girl's mysterious death? What would he say? How would he act? He seemed a smart, active, well-set-up fellow, quick, energetic, with a pair of merry grey eyes and a good-natured smile. Indeed, I took to him from the first. Yet how dare I divulge a word of what I knew? "The only thing is to wait," I suggested. "But if the Professor is in Scotland, as you say, why have you called this evening?" he asked, with some little suspicion, I thought. For the moment I was nonplussed. "I wondered whether he had returned," was my rather lame reply. "I simply called on the off-chance of seeing him." "Was your business of a pressing nature?" he asked, still wondering, I think, whether I might not have some connection with thieves who might be within. Perhaps he now suspected me of being an accomplice, set to watch outside. My hesitation when he suggested calling the police had no doubt aroused his suspicion. Besides, I suppose my agitation had caused him some surprise, for I was in deadly fear lest the police should be called, and should enter there. The dead girl's lover was a man of strongly marked character, that I could see. When once he learned the truth I should surely be suspected of having secret knowledge of the crime! "Well?" he asked, as we still stood before the closed door, "what shall we do?" "Wait," I again suggested, "the Professor is evidently still away. He may have sent Antonio across to the Continent upon some business." "If so, then there are undoubtedly thieves within. Since I've been waiting here the light in the small drawing-room overlooking the Park has been extinguished--put out, no doubt, immediately I rang. No," he went on, "we must call the police. Will you go and get a constable--or shall I?" "You go," I said, in a blank voice. "I--I'll wait here." I saw that the game was up. His suspicions were aroused, and he intended to take immediate action. "There's sure to be a policeman along at Clarence Gate," he said; "I've often noticed a man on point-duty there. But," he added, suddenly facing me and looking straight into my eyes, for the street-lamp shone brightly upon the spot where we were standing, "tell me, Mr. Holford, have you told me the actual truth?" "The truth!" I echoed. "Why, of course I have! Here is my card," and I gave him one from my cigarette-case, wherein I always carried them. He read it eagerly, and in exchange gave me one of his, laughing as he said: "I feared, perhaps, that you might be in association with the men inside. Forgive me for suspecting you, won't you?"