“I knew Inspector Hanslet had discussed the Praed Street murders with you. Or rather, in deference to your well-known insistence upon exactitude, I will say that I believed it to be in the highest degree probable. During one of my evening walks, accompanied, I may say, by one of Inspector Whyland’s charming young men, I passed your house, and saw Inspector Hanslet enter it. It was rather more than a mere guess to infer that he, who had just taken charge of the case, was about to consult you upon it.
“Then, a day or two later, I saw in The Times the announcement of your hurried departure to Australia. Believe me, Dr. Priestley, I had a higher opinion of your courage than to imagine that you had hastened to seek a place of safety. I reasoned, and events proved that I reasoned correctly, that you alone had connected the names of the dead men with those who had served on the jury at Dr. Morlandson’s trial. You were therefore aware that your own life was threatened. But one thing puzzled you. If Dr. Morlandson were dead, how could the murders be accounted for? You would naturally wish to verify his death upon the spot, but you would endeavour to do so with the utmost secrecy. Hence, I thought, the announcement of your visit to Australia, which would mislead your antagonist, and account for your absence from London. The place in which to find you alone was obviously the Isle of Purbeck.
“So I suggested a scheme to Inspector Whyland, and here my chance thought of delivering a counter to myself came in useful. I was to go to Dorchester for the week-end—I was thankful for the evidence I had already laid that the fatal period and place were the week-end and Praed Street—and he was to remain here on the watch for the assassin who threatened me. It amused me to think that the solution of the whole mystery would lie under his very eyes, for the cross-bow was on that bench, and the air-gun stands in a rack in my bedroom. But, since I had invited him, I knew that he would attach no importance to these things, even if he noticed them. I left him in possession, and went to Dorchester. But from there I took a train to Wareham, and walked across the heath to Dr. Morlandson’s cottage, where I most artistically converted Mr. Ludgrove into the Black Sailor.
“You must remember that I lived on that heath for a year, during Dr. Morlandson’s lifetime. I have been there frequently since. There is a disused clay working not far from the cottage, and in this I had secreted a number of useful articles, among them a bicycle. With this I watched in the heather, feeling certain that you would not disappoint me. You did not, and our most interesting interview took place.
“After you had started for home, I made my preparations for departure. It was just possible that you would set the local police on my track, and I was taking no risks. I rolled a round and heavy stone over the path, which gave the sand a level and untrodden appearance, and effectually removed all traces of my bicycle. Then I walked to a spot on the shores of Newton Bay, where I knew that a punt, which is very rarely used, was drawn up. In this I rowed across through the backwaters to a point on the Wareham channel above Lake. I left the punt here, turned myself back again into Mr. Ludgrove, and in the morning walked to Hamworthy Junction, whence I caught a train to Dorchester. I was in plenty of time to dig my colchicum bulbs and return to London.
“Now, Dr. Priestley, I feel that I owe you some apology. Matters have turned out very differently from what I had expected, owing to circumstances over which I have no control. I had intended that you should survive for months, even perhaps years, in daily expectation of death leaping out at you from some unexpected corner. You are a determined man, but I think you will agree that even your iron will would have broken down at last under the strain. Every now and then, when you were most absorbed in your labours, a warning would reach you, a hint that the sands were running out, that you might not be allowed time even to finish the immediate task. I think in time you would have known something of the horror of despair which grips the innocent man condemned ruthlessly and without mercy, as you condemned Dr. Morlandson, Dr. Priestley.”
The Black Sailor’s voice had become harsh and menacing, and the Professor started from his chair to meet the attack which he anticipated. But the Black Sailor waved him back again with an imperious gesture.
“Sit down, Dr. Priestley!” he commanded. “I have not yet finished what I must say and you must hear. You need fear no violence, unless you attempt to escape from this room. But you are far too sensible to make any such attempt, which, as you see, would be futile. I could overpower you in an instant, and I should then be compelled to bind you hand and foot and gag you. A most humiliating situation for you, Dr. Priestley, and one uncomfortably reminiscent of the methods of the hangman, to whose care you delivered Dr. Morlandson, you remember.”
The Professor sank back into his chair. He realized that the Black Sailor was right, that in any struggle he must inevitably be overcome, and resistance would probably lead to his immediate death. If he were to leave this room alive, it must be by strategy rather than force. It was unthinkable that the Black Sailor would release him now that he had confessed the full details of his murderous campaign. He could only bide his time, seeking some means of extricating himself from this desperate situation. But what did the man mean by his assurance that he would employ no violence?
Meanwhile the Black Sailor had continued, in the deep, pleasant voice which had been one of the most striking attributes of Mr. Ludgrove.