“That the man entered by the window at the time you say, I admit,” I said; “but why did he shut the window? It was an act which would necessarily draw the attention of those who had left it open.” “It may be the window was not shut at once,” replied the young reporter. “_But if he did shut the window, it was because of the bend in the gravel path, a dozen yards from the pavilion, and on account of the three oaks that are growing at that spot._” “What do you mean by that?” asked Monsieur Darzac, who had followed us and listened with almost breathless attention to all that Rouletabille had said. “I’ll explain all to you later on, Monsieur, when I think the moment to be ripe for doing so; but I don’t think I have anything of more importance to say on this affair, if my hypothesis is justified.” “And what is your hypothesis?” “You will never know if it does not turn out to be the truth. It is of much too grave a nature to speak of it, so long as it continues to be only a hypothesis.” “Have you, at least, some idea as to who the murderer is?” “No, monsieur, I don’t know who the murderer is; but don’t be afraid, Monsieur Robert Darzac—I shall know.” I could not but observe that Monsieur Darzac was deeply moved; and I suspected that Rouletabille’s confident assertion was not pleasing to him. Why, I asked myself, if he was really afraid that the murderer should be discovered, was he helping the reporter to find him? My young friend seemed to have received the same impression, for he said, bluntly:— “Monsieur Darzac don’t you want me to find out who the murderer was?” “Oh!—I should like to kill him with my own hand!” cried Mademoiselle Stangerson’s fiancé, with a vehemence that amazed me. “I believe you,” said Rouletabille gravely; “but you have not answered my question.” We were passing by the thicket, of which the young reporter had spoken to us a minute before. I entered it and pointed out evident traces of a man who had been hidden there. Rouletabille, once more, was right. “Yes, yes!” he said. “We have to do with a thing of flesh and blood, who uses the same means that we do. It’ll all come out on those lines.” Having said this, he asked me for the paper pattern of the footprint which he had given me to take care of, and applied it to a very clear footmark behind the thicket. “Aha!” he said, rising. I thought he was now going to trace back the track of the murderer’s footmarks to the vestibule window; but he led us instead, far to the left, saying that it was useless ferreting in the mud, and that he was sure, now, of the road taken by the murderer. “He went along the wall to the hedge and dry ditch, over which he jumped. See, just in front of the little path leading to the lake, that was his nearest way to get out.” “How do you know he went to the lake?” “Because Frédéric Larsan has not quitted the borders of it since this morning. There must be some important marks there.” A few minutes later we reached the lake.