Within a week Alderson learned that Aileen and Cowperwood were visiting an apparently private residence, which was anything but that. The house on South Sixth Street was one of assignation purely; but in its way it was superior to the average establishment of its kind—of red brick, white-stone trimmings, four stories high, and all the rooms, some eighteen in number, furnished in a showy but cleanly way. It’s patronage was highly exclusive, only those being admitted who were known to the mistress, having been introduced by others. This guaranteed that privacy which the illicit affairs of this world so greatly required. The mere phrase, “I have an appointment,” was sufficient, where either of the parties was known, to cause them to be shown to a private suite. Cowperwood had known of the place from previous experiences, and when it became necessary to abandon the North Tenth Street house, he had directed Aileen to meet him here. The matter of entering a place of this kind and trying to find any one was, as Alderson informed Butler on hearing of its character, exceedingly difficult. It involved the right of search, which was difficult to get. To enter by sheer force was easy enough in most instances where the business conducted was in contradistinction to the moral sentiment of the community; but sometimes one encountered violent opposition from the tenants themselves. It might be so in this case. The only sure way of avoiding such opposition would be to take the woman who ran the place into one’s confidence, and by paying her sufficiently insure silence. “But I do not advise that in this instance,” Alderson had told Butler, “for I believe this woman is particularly friendly to your man. It might be better, in spite of the risk, to take it by surprise.” To do that, he explained, it would be necessary to have at least three men in addition to the leader—perhaps four, who, once one man had been able to make his entrance into the hallway, on the door being opened in response to a ring, would appear quickly and enter with and sustain him. Quickness of search was the next thing—the prompt opening of all doors. The servants, if any, would have to be overpowered and silenced in some way. Money sometimes did this; force accomplished it at other times. Then one of the detectives simulating a servant could tap gently at the different doors—Butler and the others standing by—and in case a face appeared identify it or not, as the case might be. If the door was not opened and the room was not empty, it could eventually be forced. The house was one of a solid block, so that there was no chance of escape save by the front and rear doors, which were to be safe-guarded. It was a daringly conceived scheme. In spite of all this, secrecy in the matter of removing Aileen was to be preserved.