Pett fell back, staring doubtfully at Brereton's curled lip, and wondering whether to take him seriously or not. And Brereton laughed and went off--to reflect, five minutes later, that this was no laughing matter for Harborough and his daughter, and to plunge again into the maze of thought out of which it was so difficult to drag anything that seemed likely to be helpful. He interviewed Harborough again before he was taken back to Norcaster, and again he pressed him to speak, and again Harborough gave him a point-blank refusal. "Not unless it comes to the very worst, sir," he said firmly, "and only then if I see there's no other way--and even then it would only be for my daughter's sake. But it won't come to that! There's three weeks yet--good--and if somebody can't find out the truth in three weeks----" "Man alive!" exclaimed Brereton. "Your own common-sense ought to tell you that in cases like this three years isn't enough to get at the truth! What can I do in three weeks?" "There's not only you, sir," replied Harborough. "There's the police--there's the detectives--there's----" "The police and the detectives are all doing their best to fasten the crime on you!" retorted Brereton. "Of course they are! That's their way. When they've safely got one man, do you think they're going to look for another? If you won't tell me what you were doing, and where you were that night, well, I'll have to find out for myself." Harborough gave his counsel a peculiar look which Brereton could not understand. "Oh, well!" he said. "If _you_ found it out----" He broke off at that, and would say no more, and Brereton presently left him and walked thoughtfully homeward, reflecting on the prisoner's last words. "He admits there is something to be found out," he mused. "And by that very admission he implies that it could be found out. Now--how? Egad!--I'd give something for even the least notion!" Bent's parlour-maid, opening the door to Brereton, turned to a locked drawer in the old-fashioned clothes-press which stood in Bent's hall, and took from it a registered letter. "For you, sir," she said, handing it to Brereton. "Came by the noon post, sir. The housekeeper signed for it." Brereton took the letter into the smoking-room and looked at it with a sudden surmise that it might have something to do with the matter which was uppermost in his thoughts. He had had no expectation of any registered letter, no idea of anything that could cause any correspondent of his to send him any communication by registered post. There was no possibility of recognizing the handwriting of the sender, for there was no handwriting to recognize: the address was typewritten. And the postmark was London.