Muller threw on his coat hastily. “You didn’t pay him, did you? On a cold day like this the drivers don’t like to wait long in any one place.”
“No danger. I haven’t money enough for that,” replied Amster with a sad smile. Muller did not hear him as he was already outside. But the commissioner with whom he had been talking and to whom Muller had already spoken of his voluntary assistant, entered into a conversation with Amster, and said to him finally: “I will take it upon myself to guarantee your future, if you are ready to enter the secret service under Muller’s orders. If you wish to do this you can stay right on now, for I think we will need you in this case.”
Amster bowed in agreement. His life had been troubled, his reputation darkened by no fault of his own, and the work he was doing now had awakened an interest and an ability that he did not know he possessed. He was more than glad to accept the offer made by the official.
Muller was already across the street and had laid his hand upon the door of the cab when the driver turned to him and said crossly, “Some one else has ordered me. But I am not going to wait in this cold, get in if you want to.”
“All right. Now tell me first where you drove to last evening with the sick lady and her companion?” The man looked astonished but found his tongue again in a moment. “And who are you?” he asked calmly.
“We will tell you that upstairs in the police station,” answered Muller equally calmly, and ordered the man to drive through the gateway into the inner courtyard. He himself got into the wagon, and in the course of the short drive he had made a discovery. He had found a tiny glass stopper, such as is used in perfume bottles. He could understand from this why the odour of perfume which had now become familiar to him was still so strong inside the old cab. Also why it was so strong on the delicate handkerchief. Asta Langen had taken the stopper from the bottle in her pocket, so as to leave a trail of odour behind her.
Fifteen minutes after the driver had made his report to Commissioner Von Mayringen, the latter with Amster entered another cab. A well-armed policeman mounted the box of this second vehicle. “Follow that cab ahead,” the commissioner told his driver. The second cab followed the one-horse coupe in which Muller was seated. They drove first to No. 14 Cathedral Lane, where Muller told Berner to come with him. He found Mr. Fellner ready to go also, and it was with great difficulty that he could dissuade the invalid, who was greatly fatigued by his morning visit to the police station, from joining them.