More, on the forehead there is this extraordinary impressed mark of a Red Triangle. Now, what can all that mean? Robbery, perhaps one thinks. But the body isn't robbed! There are three five-pound notes on it, besides a sovereign or two and some small change, a watch and chain, keys and all the rest of it. Then one guesses at the diamonds. Perhaps it was an accomplice in the robbery, who finds that Denson is about to bolt with the whole lot. But if there's one thing plain in this amazing business it is that Denson had no accomplice; he did the whole thing alone, as you discovered, and he needed no help. More than that, if this were the work of an accomplice why didn't he get the jewels? There were the keys to his hand and he left them! And would such a person actually go out of his way to put the body where it must be discovered at once, instead of concealing it till he could himself get away with the diamonds? Of course not. But there was no accomplice, and it's useless to labour that farther. All these arguments apply equally against the theory that it was the work of some criminal gang. They would have taken all they could get, notes, keys, diamonds and all, and they wouldn't have been so foolish as to exhibit the body with that extraordinary mark; criminal gangs are not such fools as to take unnecessary chances and gratuitously leave tracks behind them, as you know well enough. Well then, there we stand. So far, do you see any more in it than I do?"
Hewitt shook his head. "No," he said, "I can't say I do. All the considerations you have mentioned have already occurred to me. I talked them over, in fact, with my friend Brett. My connection with the case ceased, of course, with the discovery of the jewels, and about the murder I know no more than has been told me. I never saw the body, and so had no opportunity of picking up any overlooked clue; though doubtless you have seen to that. I know not a tittle more than you have just summarised, and on that alone the thing seems mystery pure and unadulterated."
"All there is beyond that was ascertained by the divisional surgeon on examination of the body. The man died from strangulation, as you know, and the natural presumption from that was that the murderer must have been a powerful man. But the surgeon is of the positive opinion – he is certain, in fact – that Denson was strangled with an instrument – a tourniquet."
"A tourniquet?"
"Yes, a surgeon's tourniquet, such as is used to compress a leg or arm and so stop a flow of blood. He considers the marks unmistakable. Now that might point to the murderer being a medical man."
"Conjecturally, yes; though, of course, it justifies nothing more than conjecture."
"Precisely. Well, that was something, but precious little. A tourniquet is a common thing enough – no more than a band with screw fittings, and there was nothing to show that the tourniquet used was any different from a thousand others; and I can see no particular reason why a doctor should commit a murder like this any more than any other man; in which the divisional surgeon agreed with me. And doctor or none, that Red Triangle was altogether unaccounted for. About that, too, by the way, the divisional surgeon told me a little, but a very useless little. The mark was not properly dried, owing to its slightly greasy nature, and although it was almost impossible to remove it wholly, it was possible to scrape off a little of the ink, or colour. Here is a little of it on a paper – quite dried now, of course."
Plummer carefully took from his pocket a small folded paper, unfolded it, and revealed a smaller paper within. On this were two little smears of a bright red colour. "There – that's the stuff," he said. "The surgeon examined it, and he reports it to be rather oddly constituted – so as to bear some affinity of meaning, possibly, to the triangle. For the stuff is a compound of three substances – animal, vegetable and mineral; there is a fine vegetable oil, he says, some waxy preparation, certainly of animal origin, and a mineral – cinnabar: vermilion, in fact. But though there may be some connection between the triangle and the substances representing the three natural kingdoms, it gives nothing practical – nothing to go on."
Martin Hewitt had been closely examining the marks on the paper, and now he answered, "I'm not so sure of that, though, Plummer. I think at least that it gives us another conjecture. I should guess that the man you want, as well as being acquainted with the use of the tourniquet, has at some time travelled in, or to, China."
"Why?"
"Unless I am wider of the mark than usual, this is the pigment used on Chinese seals. A Chinaman's seal acts for his signature on all sorts of documents; it is impressed or printed by hand pressure from a little engraved stone die, precisely as this triangle seems to have been, and the ink or colour is almost always red, compounded of vermilion, wax, and oil of sesamum."
Plummer sat up with a whistle. "Phew! Then it may have been done by a Chinaman!"
Hewitt shrugged his shoulders. "It's possible," he said; "of course, though, the sign, the triangle, is not a Chinese character. As a character, of course it is the Greek Delta. But it may be no character at all. In the signs of the ancient Cabala, the triangle, apex upward as it was in this case, was the symbol of fire; apex downward, it signified water."
Plummer patted the side of his head distractedly. "Heavens!" he said, "don't tell me I'm to search all China, and Greece, and – wherever the cabalistic pundits come from!"
"Well, no," Hewitt answered with a smile. "I think I should, at any rate, begin in this country. I rather think you might make a beginning at Denson. That is what I should do if the case were mine. See if anything can be ascertained of his previous life – probably under another name or names. He may have been in China. Yes, certainly, as we stand at present, I should begin at Denson."
"I think I will," the inspector replied, "though there's precious little to begin on there. I'd like to have you with me on this job, but, of course, that's impossible, since it's purely a police matter. But something, some information, may come your way, and in that case you'll let me know at once, of course."
"Of course I shall – it's a serious matter, as well as a strange one. I wish you all luck!"
Plummer departed to grapple with his difficulties, but in fact it was Hewitt who first heard fresh news of the Red Triangle, and that from a wholly unexpected quarter.
It was, indeed, only two days after Plummer's visit that Kerrett brought into Hewitt's private room the card of the Rev. James Potswood, with a request for a consultation. Mr. Potswood's name was known to Hewitt, as, indeed, it was to many people, as that of a most devoted clergyman, rector of a large parish in north-west London, who devoted not only all his time and personal strength to his work, but also spent every penny of his private income on his parish. It was not a small income that Mr. Potswood spent in this unselfish way, for he came of a wealthy family, and though a good part of his parish was inhabited by well-to-do people, there was quite enough poverty and distress in the poorer quarters to cause this excellent man often to regret that his resources were not even larger. He was a spare active grey-whiskered man of nearly sixty, with prominent and not very handsome features, though his face was full of frank and simple kindliness.
"My errand, Mr. Hewitt," he said, "is of a rather vague, not to say visionary, character, and I doubt if you can help me. But at any rate I will explain the trouble as well as I can. In the first place, am I right in supposing that you were in some way professionally engaged in connection with that extraordinary case of murder a week or so ago – the case in which a man named Denson was found dead on the steps by the Duke of York's column?"
"Yes – and no," Hewitt answered. "I was professionally engaged on a certain matter about which you will not wish me to particularise – since it is the business of a client – and in course of it I came upon the other affair."
"Then before I ask what you know of that mysterious event, Mr. Hewitt, I will tell you my story, so that you may judge whether you are able to reveal anything, or to do anything. Of course, what I say is in the strictest confidence."
"Of course."
"I have a parishioner, a Mr. Jacob Mason, of whom I have seen very little of late years – scarcely anything at all, in fact, till a few days ago. He is fairly well to do, I believe, living a somewhat retired life in a house not far from my rectory. For many years he has laboured at natural science – chemistry in particular – and he has a very excellently fitted laboratory attached to his house. He is a widower, with no children of his own, but his orphan niece, a Miss Creswick,