"She admits having handed over the jewels to Lola, but she won't say a word beyond that," he said. "She's as obstinate as a mule. I have told the Duke something of where we stand, and he has agreed to take the gems back without letting her know. It was a tough job, but I got him to see at last that the girl might be implicating herself. He says he's never heard of Petrovska." "H'm." Foyle rubbed his chin vigorously. "I'll have a talk with the old boy. See if you can get the Public Carriage Office to borrow us a taxicab, and get Poole to drive it slowly up and down this street. If she hails it when she goes out, well and good. If not, Bolt and you had better follow her, and the cab will come after you so that you can use it in emergency." Green had done his work with the Duke and the lawyer with tact. Foyle found his interview with them confined to evading questions that he had no wish to answer. He dismissed them at last with the jewels in the custody of the man of the law. Then he went straight to his prisoner. "You can go," he said abruptly. "I shall ask you to be very careful, however, Princess. If you are wise you will leave England at once." "Why?" she asked, opening her blue eyes wide and gazing at him with blank astonishment. His voice became silky. "Because, my dear lady," he said, "I feel that your career in England may not be altogether without reproach. I shall try to find out a little more about it, and if I get a chance, I warn you frankly, I shall have you taken into custody. You are too mischievous to be allowed to run around loose." Her red lips parted in a scornful smile. "Oh, you make me tired," she retorted. "Good-bye, Mr. Foyle." "Pardon me," he said, and thrusting a couple of fingers into his waistcoat pocket, fished out a piece of paper. "Do you know this writing?" She handed the piece of paper back to him with a shake of the head. "No. I never saw it before," she retorted, and passed out. But Heldon Foyle had her finger-prints. CHAPTER XXII Sir Hilary Thornton lifted his coat-tails to the cheerful blaze as he stood with his back to the fireplace. Heldon Foyle, with the book which he was giving his nights and days to compiling on the desk in front of him, sat bolt upright in his chair talking swiftly. He was giving an account of the progress of the investigation. Now and again he ran a well-manicured finger down the type-written index and turned the pages over quickly to refer to a statement, a plan, or a photograph. Or he would lift one of the speaking-tubes behind his desk and send for some man who had been charged with some inquiry, to question him on his report.