Fantomas, after killing Susy d'Orsel, had lurked on the stairs until the King left the apartment. Then, locking the door, he had hurried after his victim and caught him at the moment he reached the cellar. The detective's next move was to break into the apartment of the Marquis de Serac. By the aid of a ladder which he found in a corner, he climbed up and broke a windowpane and thus made his entrance. At first nothing in the apartment seemed worthy of suspicion. The rooms were elegant but commonplace. The bureaus and wardrobes were locked, and gave out a hollow sound when rapped upon. As he did not have his burglar's equipment with him, Juve decided to come back later and investigate. He was on the point of leaving when his foot caught in a garment, which he found to be a waistcoat. He gave vent to an exclamation of surprise as he picked it up and folding it into a bundle hid it under his overcoat. The Marquis de Serac had been under his suspicion for some time; now that suspicion was in a fair way to become a certainty. Were the Marquis and Fantomas one and the same? Juve was inclined to answer in the affirmative.... * * * * * The next step was to invite Wulf to dine with him, to show him the waistcoat and prove beyond doubt that it had been made by a tailor of Glotzbourg. Juve's opinion had now become a solid conviction. Fantomas had worn the garment, and had carried the diamond in the pocket of the waistcoat he found in the Marquis de Serac's apartment. Hence the Marquis de Serac was Fantomas. CHAPTER XXVII THE EXPLOSION OF THE NORD-SUD The Empire clock on Juve's desk struck half-past eleven. The detective, having gone over in his mind the course of events just narrated, rose abruptly and tapped Wulf on the shoulder. "Monsieur Wulf, if you are to remain here you are very welcome to do so; as for me, I'm going out." Wulf, wakened out of a doze, sat up and stared at Juve, an expression of dawning suspicion in his eyes. "Where are you going?" he inquired. Juve, absorbed in his thoughts, did not remark the strange behavior of his colleague. He had settled on a plan of action, which was simply to arrest the Marquis de Serac. "Oh, I'm just going ... for a walk." "All right, get your hat." A few moments later the two men hailed a taxi and drove to 247 Rue de Monceau. During the trip Juve pumped Wulf about his relations with Fandor, and it appeared that the latter had pursued the policy of making Wulf drunk upon every occasion. Doubtless, the detective reasoned, it was thus that Fandor was enabled to escape for an hour, during which time the substitution had been effected. Wulf explained how he had found the King near the fountains in the Place de la Concorde, and Juve realized that in some way or other the King and the fountains were mysteriously connected. In his turn, Wulf plied Juve with questions as to what he had done during his stay at Glotzbourg.