Clyde Burke made mental note of two men in evening clothes who were entering the apartment house.
Then he raised an objection.
“There are forty stories in the Marimba Apartments,” he said. “People come and go all evening. How do we know which ones call on Palermo?
“You have a car in the street, waiting to follow any visitor who may leave — but which are Palermo’s visitors, and which are not?”
Harry Vincent laughed.
“I might mention,” he said, “that the night elevator operator at the Marimba Apartments was discharged two days ago. His place has been taken by a new man — a quiet chap, Burbank. I may add that Burbank is one of The Shadow’s operatives.”
Clyde Burke uttered an exclamation of surprise.
“Burbank will notify us,” continued Harry. “That is why we are keeping tabs on all arrivals. The first person who calls on Doctor Palermo will be watched on his way to the fortieth floor. We will be notified.”
The effectiveness of The Shadow’s system captured Clyde’s admiration. He realized that he had became an integral part of a smooth machine that was already forcing Doctor Palermo into a helpless position.
Either the murderous physician would be forced to admit defeat and remain a virtual prisoner in his turret above the fortieth floor; or he would be compelled to make a counterstroke that would render him vulnerable.