“Do you mind coming into the study with me again, doctor? There are one or two things I want to ask you.”
I acquiesced. Inspector Davis unlocked the door of the lobby, we passed through, and he locked the door again behind him.
“We don’t want to be disturbed,” he said grimly. “And we don’t want any eavesdropping either. What’s all this about blackmail?”
“Blackmail!” I exclaimed, very much startled.
“Is it an effort of Parker’s imagination? Or is there something in it?”
“If Parker heard anything about blackmail,” I said slowly, “he must have been listening outside this door with his ear glued against the keyhole.”
Davis nodded. “Nothing more likely. You see, I’ve been instituting a few inquiries as to what Parker has been doing with himself this evening. To tell the truth, I didn’t like his manner. The man knows something. When I began to question him, he got the wind up, and plumped out some garbled story of blackmail.”
I took an instant decision. “I’m rather glad you’ve brought the matter up,” I said. “I’ve been trying to decide whether to make a clean breast of things or not. I’d already practically decided to tell you everything, but I was going to wait for a favourable opportunity. You might as well have it now.”
And then and there I narrated the whole events of the evening as I have set them down here. The inspector listened keenly, occasionally interjecting a question.
“Most extraordinary story I ever heard,” he said, when I had finished. “And you say that letter has completely disappeared? It looks bad—it looks very bad indeed. It gives us what we’ve been looking for—a motive for the murder.”