With his finger outstretched toward the ruins, he traced in the air a little circle which became smaller and smaller until it was only a point. And that point his two companions sought desperately, both leaning into space, both moved by the same faith in Beautrelet and quivering with the ardent conviction which he had forced upon them. Yes, Arsène Lupin was there. In theory and in fact, he was there: neither of them was now able to doubt it. And there was something impressive and tragic in knowing that the famous adventurer was lying in some dark shelter, below the ground, helpless, feverish and exhausted. “And if he dies?” asked M. Filleul, in a low voice. “If he dies,” said Beautrelet, “and if his accomplices are sure of it, then see to the safety of Mlle. de Saint-Véran. Monsieur le Juge d’Instruction, for the vengeance will be terrible.” A few minutes later and in spite of the entreaties of M. Filleul, who would gladly have made further use of this fascinating auxiliary, Isidore Beautrelet, whose holidays ended that day, went off by the Dieppe Road. He stepped from the train in Paris at five o’clock and, at eight o’clock, returned to the Lycée Janson together with his schoolfellows. Ganimard, after a minute, but utterly useless exploration of the ruins of Ambrumésy, returned to Paris by the fast night-train. On reaching his apartment in the Rue Pergolese, he found an express letter awaiting him: _Monsieur l’Inspecteur Principal:_ Finding that I had a little time to spare at the end of the day, I have succeeded in collecting a few additional particulars which are sure to interest you. Arsène Lupin has been living in Paris for twelve months under the name of Étienne de Vaudreix. It is a name which you will often come across in the society notes or the sporting columns of the newspapers. He is a great traveler and is absent for long periods, during which, by his own account, he goes hunting tigers in Bengal or blue foxes in Siberia. He is supposed to be in business of some kind, although nobody is able to say for certain what his business is. His present address is 38, Rue Marbeuf; and I will call your attention to the fact that the Rue Marbeuf is close to Post-office Number 45. Since Thursday the twenty-third of April, the day before the burglary at Ambrumésy, there has been no news at all of Étienne de Vaudreix. With very many thanks for the kindness which you have shown me, believe me to be, Monsieur l’Inspecteur Principal, Yours sincerely, ISIDORE BEAUTRELET.