“It’s no use to look,” replied Kennedy, as I started for the hall. “They are as ignorant as we are. See—the wire doesn’t go there. It goes horizontally to that box or casing in the corner which carries steam-pipes. Then it goes down. It’s not likely it goes down very many floors. Let’s see what’s under us.”

The office beneath bore on its doors the name of a well-known brokerage firm. There was no reason to suspect them, and Kennedy and I walked down another floor. There, in a little office, directly under that occupied by Hastings, gilt letters announced simply “Public Stenographer Exchange.” Without a doubt that was the other end of the eavesdropper.

“There’s no one in yet, sir,” informed a cleaning woman who happened to see us trying the door.

Kennedy was ready with a story. “That’s too bad,” he hastened, with a glance at his watch. “They want to sublet it to me and I’d like to look at it before I decide on another office at nine o’clock.”

“I can let you see it,” hinted the woman, rattling a string of keys.

“Can you?” encouraged Kennedy, slipping a silver coin into her hand. “Thank you. It will save me another trip.”

She opened the door and we saw at once why Kennedy’s chance story had seemed so plausible. Whatever furniture had been there had been moved out, except a single plain chair and a very small table. But on the table stood a box, the receiving end of the detectaphone. It was the eavesdropper’s station, all right.

The woman left us a moment and we made the best of the opportunity. Not even a scrap of paper had been left. Except for what greeted us on our first entrance, there was nothing.

Who had rented the place? Who had listened in, had heard and anticipated even our careful frame-up?

Could it have been that this was the objective of the hasty visit of Paquita, that it had been she who was so eager to destroy the evidence of the eavesdropping on Hastings?