“This is the vengeance which I had planned for you, Dr. Priestley. But, unfortunately, my plans have been thwarted. Long ago, when Dr. Morlandson was alive, he warned me that, well set up and healthy as I appeared to be, my heart was affected by organic disease. He told me frankly that it might be many years before it seriously affected my health, and that, with reasonable care, I might expect to attain the average term of years. But at the same time he warned me that my trouble might at any time become acute, and he described to me the symptoms which would be my signal to prepare for death.
“Those symptoms developed last week, Dr. Priestley, and I knew that I had only a short while longer to live. But I was determined not to die leaving the vengeance which had been bequeathed to me unaccomplished. I had sworn to be the instrument of justice upon those who had destroyed Dr. Morlandson’s life, for that life had been destroyed just as surely as though his original sentence had been carried out. And of those who had incurred the guilt, only you remained, Dr. Priestley.
“I could have shot you in your own house, and then turned the weapon upon myself. In any case I am to die very shortly, and I much prefer death at my own hands and under my own control to the anxious waiting for the uncertain hand of nature. It would have been the easiest way, perhaps, but it was not in accordance with the methods which I had so carefully developed. How much more fitting it would be that you should die in Praed Street, that your death should be the culminating point in the history of the murders in Praed Street! I believed that it could be done, and I set myself to work out the details.
“The police, as you are aware, have rather lost interest in you and me. The discovery of the knife in Mr. Copperdock’s coat pocket seems finally to have convinced them that the secret died with him, and, whatever the secret might have been, no further murders were to be anticipated. Detectives are busy people, they have no time to spare for academic research. I am sure that they are convinced that no actual danger menaces either Dr. Priestley or Mr. Ludgrove, although both of them are known to have received numbered counters. They were not likely to interfere with my schemes.
“You are aware of the steps which I took to bring you here. Had you refused to accompany me this evening, I should have shot you outright in your own study. But I knew that you would not refuse. The solution of the mystery had become a point of honour with you, and, besides, you had a message for me which I was sure that you would be glad of the opportunity to deliver. Surely you would not have hesitated to give the innocent Mr. Ludgrove the Black Sailor’s message, Dr. Priestley?”
The Professor forced a smile. “I had intended to do so, but—he died, to use your own expression, before I had the opportunity.”
“Yes, that was unfortunate,” agreed the Black Sailor pleasantly. “But still, the fact that you had the message to deliver served its purpose. It was an added inducement to you to accept my invitation. And, by carefully emphasizing the possible danger which lurked in Praed Street, I worked upon your pride. You would not have refused to come with me, after that. And I told you the truth, I had revelations to make which I knew would interest you, and I think you have not been disappointed.”
He paused for a moment, and then continued, a sinister purpose in his voice: “And now the end has come. It is not the end I sought, but I welcome it as well as any other. We two will pass out of this world together, Dr. Priestley, you the last victim of my justice, and I the executioner. It is but anticipating my own death for a short time, and the means I shall employ will render even deeper the mystery which surrounds me. On Sunday morning the world will hear of two more strange deaths in Praed Street. I think your secretary will come round here before the night is over, and, being able to obtain no reply, will call in the police to his aid. How much of the riddle will they solve, I wonder?”
The Black Sailor stretched out his hand, and switched on a small electric hand-lamp which stood on a table by his side. “That will give us sufficient light for our purpose,” he said sombrely. Then, before the Professor could guess his intention, he suddenly leapt from his chair, turned out the gas which was burning at a bracket by the mantelpiece, and with a powerful wrench tore the bracket itself from the wall. It fell with a crash into the fire-place.
Then the Professor understood. He, too, leapt from his chair with a shout, and dashed blindly for the door. But the Black Sailor was there before him. “It is useless, Dr. Priestley,” he said menacingly. “The door is fastened securely, as is the window. The chimney is blocked, and there is no possible escape for us. I doubt if you would be heard if you call again for help, but I cannot risk it. Will you give me your word to wait quietly, or must I gag you and tie you up? Would you care to meet death bound like a criminal, Dr. Priestley?”