"Yes," Jim agreed.

"We were detained for a few minutes by Maurice Thevenet. Yes." He moistened his lips with the tip of his tongue and said softly: "We shall have to consider that very modest and promising young gentleman rather carefully. He detained us. We heard the clock strike half-past ten as we waited in the street."

"Yes."

"And all was over then. For the house was as silent as what, indeed, it is—a grave. And only just over, for the body is still warm. If this—lying here, is Jean Cladel, some one else must have been waiting for him to come home to-night, waiting in the lane behind, since my man didn't see him. And an acquaintance, a friend—for Jean Cladel lets him in and locks the door behind him."

Jim interrupted.

"He might have been here already, waiting for him with his knife bared in this dark room."

Hanaud looked around the room. It was furnished cheaply and stuffily, half office, half living-room. An open bureau stood against the wall near the window. A closed cabinet occupied the greater part of one side.

"I wonder," he said. "It is possible, no doubt—— But if so, why did the murderer stay so long? No search has been made—no drawers are ransacked." He tried the door of the cabinet. "This is still locked. No, I don't think that he was waiting. I think that he was admitted as a friend or a client—I fancy Jean Cladel had not a few clients who preferred to call upon him by the back way in the dark of the night. I think that his visitor came meaning to kill, and waited his time and killed, and that he had hardly killed before we rang the bell at the door." Hanaud drew in his breath sharply. "Imagine that, my friend! He is standing here over the man he has murdered, and unexpectedly the shrill, clear sound of the bell goes through the house—as though God said, 'I saw you!' Imagine it! He turned out the light and stands holding his breath in the dark. The bell rings again. He must answer it or worse may befall. He goes into the front room and throws open the window, and hears it is the police who are at the door." Hanaud nodded his head in a reluctant admiration. "But that man had an iron nerve! He doesn't lose his head. He closes the shutter, he turns on the light, that we may think he is getting up, he runs back into this room. He will not waste time by stumbling down the stairs and fumbling with the lock of the back door. No, he opens these shutters and drops to the ground. It is done in a second. Another second, and he is in the lane; another, and he is safe, his dreadful mission ended. Cladel will not speak. Cladel will not tell us the things we want to know."

Hanaud went over to the cabinet and, using his skeleton keys, again opened its doors. On the shelves were ranged a glass jar or two, a retort, the simplest utensils of a laboratory and a few bottles, one of which, larger than the rest, was half filled with a colourless liquid.

"Alcohol," said Hanaud, pointing to the label.