Just as a cab drew up to the kerb I arrived on the scene. I had been kept closely informed of what was going on and had been waiting in a neighbouring restaurant in order to be present at the arrest of the two plotters. Incautiously I approached too near, and in the light of a street-lamp van Rosen caught sight of me. He recognised me instantly. With a snarl of rage he turned on me, and his hand shot to his hip-pocket. Then he recovered his self-possession and entered the taxi with Easterbrook. No doubt he reflected that a shot at me would not help him, and, it should be noted, neither man had any incriminating document on him. The "plans" were in possession of the Dutch sailor, and until they were secured we had to hold our hands. But one quarry was safe now. The taxi soon deposited the two men at Easterbrook's house, which was immediately closely surrounded. Half an hour later Madame Gabrielle, hatless and showing every sign of a struggle, slipped from a side door. Breathlessly she explained that van Rosen, catching sight of her as he was going to his room on the first floor, had recognised her at once and had attacked her furiously. Why he did not shoot her I never could understand. Physically Madame Gabrielle was a match for him; she was a superb gymnast and in hard training, whereas van Rosen had been leading a dissipated life and was in thoroughly poor condition. A brief struggle had ended in Madame Gabrielle throwing him heavily by a simple wrestling trick, and, knowing that she must get away at all cost, she had rushed down the back stairway and got into the street. A moment or two later a servant left the house and posted some letters in the pillar-box a few yards away. The letters were recovered later, and one of them, a postcard, was found to be addressed to Jules Cauvin. It was in a feminine handwriting, and bore neither the date nor the address of the writer. It read: "My dear Jules,--Henri will return home to-morrow. He has immensely enjoyed his visit, and his health has greatly improved. "Yours, "Marie." Innocent enough, but--_the card was perfumed with violets_! Clearly enough its purpose was to let Cauvin know that danger was in the air. We were expecting every moment the news that the Dutch sailor had been arrested with the incriminating documents in his possession. That would have been the signal for the arrest of Easterbrook and van Rosen. But the arrest was not to be made. Far away to the east we heard the low boom of a gun. Another and another followed; then came the crash of high explosives, and we realised that an air raid was in progress. Nearer and nearer came the sounds of guns and bombs. Suddenly I picked up the drone of an aerial motor directly overhead, and a few seconds later came an appalling crash that seemed to shake the very earth. I saw a red blaze flash out over Easterbrook's house, and after that everything was a blank.