Chapter 14
Mason unlocked the door which led to his private office. Receding Paul Drake into the room, he switched on the lights and silently tiptoed over to the picture behind which they had discovered the microphone. He nodded to Paul Drake, and together, each taking a corner of the picture, they lifted it once more away from the wall. There was no sign of the microphone. A very faint difference in color on the plaster indicated where it had been freshly patched with a quick-drying compound. Mason said, “Well, Paul, that’s that.”
Drake, staring at the unbroken expanse of plaster, said, “Do you suppose it’s somewhere else?”
“No,” Mason told him. “They’ve pulled it out, lock, stock, and barrel.”
“Why? Because it served its purpose?”
“No,” Mason said, “because they knew we were wise to it.”
“How did they know that?”
Mason said, “It’s my fault, Paul. I didn’t realize it until afterwards.”
“Realize what, Perry?”
“You remember that after I discovered the microphone, I went out to the typewriter and typed out a message.”