Muller turned on the instant, for he had heard the door on the other side of the hall open, and a tall slender man with a smooth face and a deep scar on his right cheek stood on the threshold looking at them in dazed surprise. For an instant only had he lost his control. The next second he was in his room again, slamming the door behind him. But it was too late. Amster’s foot was already in the crack of the door and he pushed it open to let Muller enter. “Well done,” cried the latter, and then he turned to the man in the room. “Here, stop that. I can fire twice before you get the window open.”
The man turned and walked slowly to the centre of the room, sinking down into an arm-chair that stood beside the desk. Neither Amster nor Muller turned their eyes from him for a moment, ready for any attempt on his part to escape. But the detective had already seen something that told him that Langen was not thinking of flight. When he turned to the desk, Muller had seen his eyes glisten while a scornful smile parted his thin lips. A second later he had let his handkerchief fall, apparently carelessly, upon the desk. But in this short space of time the detective’s sharp eyes had seen a tiny bottle upon which was a black label with a grinning skull. Muller could not see whether the bottle was full or empty, but now he knew that it must hold sufficient poison to enable the captured criminal to escape open disgrace. Knowing this, Muller looked with admiration at the calmness of the villain, whose intelligent eyes were turned towards him in evident curiosity.
“Who are you and who else is here with you?” asked the man calmly.
“I am Muller of the Secret Service,” replied his visitor and added, “You must put up with us for the time being, Mr. Egon Langen. The police commissioner is occupied with your step-sister, whom you were about to murder.”
Langen put his hand to his cheek, looking at Muller between his lashes as he said, “To murder? Who can prove that?”
“We have all the proofs we need.”
“I will acknowledge only that I wanted Asta to disappear.”
Muller smiled. “What good would that have done you? You wanted her entire fortune, did you not? But that could have come to you only after thirty years, and you are not likely to have waited that long. Your plan was to murder your step-sister, even if you could not get a letter from her telling of her intention to commit suicide.”
Langen rose suddenly, but controlled himself again and sank back easily in his chair. “Then the old woman has been talking?” he asked.
Muller shook his head. “We knew it through Miss Langen herself.”