At six o’clock, Wenk, disguised as a cyclist messenger, went into the empty villa, leaving his bicycle outside. He was quite alone in the house, and at once sought for a window which would afford him vantage ground. He concealed himself behind a lace curtain and began to watch the street. The first thing he noticed was that after he had been there about a quarter of an hour someone stole his bicycle and made off with it. He had never seen a thief actually at work before; this side of his calling was presented to him for the first time to-day. He regarded it as a favourable omen, being much amused by the comic haste with which the thief had looked round him on all sides, although he was even then straddling the machine. For two hours he kept watch on the front door, side door, window and roof of Mabuse’s villa. No one went out or in, and though Wenk remained on the watch till midnight, nothing was to be seen. He fell asleep at the window, woke and watched again, and then slept once more, finally awaking in broad daylight. His servant brought him a meal prepared in a restaurant near. It was a long vigil, and Wenk, bringing the telephone to the window, held conversations with acquaintances and with some members of the police force. At last, towards six o’clock in the evening, a car drew up and immediately drove away again. A gentleman went up to the front door. Was it Mabuse? No, this was an old gentleman, with the feeble and uncertain step of a paralytic. Possibly he was a patient. Soon after that Wenk saw a chimney-sweep leave the house. He went along quickly and cheerfully, puffing away at a cigarette. Wenk had not seen the sweep go in; that must have been mere chance, though. The old invalid seemed to be there a long time; could he be waiting for the Doctor? Perhaps, though, he was one of his assistants. It seemed hardly likely. However, he must do nothing rash. Twilight was already advanced when a man with a parcel rang at the front door, which was opened with surprising promptness. Half an hour later this man came out again, and so it went on. Even through the night people kept coming and going, and next day it was the same story. On the third day Wenk was called up early by his man. The Criminal Investigation Department had some important information for him. Something had happened during the night at a gaming-den. Would he like an official to bring him a report? Yes, he replied, but the detective should come in some sort of uniform.