Five minutes later he had overtaken Madame Bohman, and, walking side by side for a few hundred yards, they had a brief conversation and parted. Our agent was in a quandary. He had the strictest instructions not to lose sight of Madame Bohman, but he was a man of intelligence, and realised that a new factor had appeared on the scene. Accordingly, he decided to follow the man, and soon saw him enter a cheap boarding-house, letting himself in with a latchkey. Five minutes later we had the news, and a couple of men were at once detailed to take up the watch. Madame Bohman, we soon ascertained, had gone straight to her hotel. The boarding-house which the mysterious stranger had entered was closely watched all night. The next morning the man came out, and was immediately recognised as none other than Halbmayr himself! How he had got into France and Paris was a mystery, for the police had no register of his arrival. I may say here that this point was never completely cleared up, but it was very generally believed that he was put ashore by a submarine, and intended leaving in the same way. We now had him safely enough; he could not possibly escape. He was a known spy, and there was ample ground for arresting him. But this would have made mincemeat of our plans, as Hecq saw plainly enough. "Halbmayr is very dangerous," he declared to me as I sat in his office the same day. "Evil work is on foot somewhere, and our friend the German is director of operations. He would not dare to show his face in France after meeting Brahe in Lisbon unless he were playing for a big coup. But, my dear Sant, what is his motive? What is he after? To that question so far we have got no reply whatever. And we _must_ find the answer." I agreed with my chief most cordially. "Give him rope," I said, "and see if he does not hang himself. At any rate, he won't escape us this time; we shall get him even if we don't learn his secret. What worries me is that he may have done his nefarious work, and inflicted untold injury on the Allies before we nab him. But we must take some chances." "The telegram sent by Brahe, or Thornton, to Engstrom just before the former left Lisbon mentioned two things," said my chief. "The first was that Johnson-Meads was with them--in other words, that his suspicions had been allayed (which we know to be a fact)--and that `T.' was here in Paris `to arrange further details and transit of machinery.' What machinery? And who is `T'? `T' must be Tegelmund, the man in Marseilles. We must look out for him." CHAPTER SEVENTEEN. "THE PLOT REVEALED." Within a week the man Tegelmund, accompanied by Engstrom, arrived in Paris and took up his abode in an obscure hotel near the Gare du Nord. But, though we kept a careful watch upon the pair, Engstrom, ever elusive and resourceful, suddenly disappeared! For six days he was absent. Then, as suddenly and mysteriously, he appeared again at the hotel.