"And Li Chang Yen?" inquired Poirot. "Naturally nothing is traced to him, but there are signs, eh?"
Mr. Ingles shrugged.
"Oh, signs—yes, certainly. And once I found a man who would talk, a brilliant young Chinese chemist who was a protégé of Li Chang Yen's. He came to me one day, this chemist, and I could see that he was on the verge of a nervous breakdown. He hinted to me of experiments on which he'd been engaged in Li Chang Yen's palace under the mandarin's direction—experiments on coolies in which the most revolting disregard for human life and suffering had been shown. His nerve had completely broken, and he was in the most pitiable state of terror. I put him to bed in a top room of my own house, intending to question him the next day—and that, of course, was stupid of me."
"How did they get him?" demanded Poirot.
"That I shall never know. I woke that night to find my house in flames, and was lucky to escape with my life. Investigation showed that a fire of amazing intensity had broken out on the top floor, and the remains of my young chemist friend were charred to a cinder."
I could see from the earnestness with which he had been speaking that Mr. Ingles was a man mounted on his hobby horse, and evidently he, too, realised that he had been carried away, for he laughed apologetically.
"But, of course," he said, "I have no proofs, and you, like the others, will merely tell me that I have a bee in my bonnet."
"On the contrary," said Poirot quietly, "we have every reason to believe your story. We ourselves are more than a little interested in Li Chang Yen."
"Very odd your knowing about him. Didn't fancy a soul in England had ever heard of him. I'd rather like to know how you did come to hear of him—if it's not indiscreet."
"Not in the least, monsieur. A man took refuge in my rooms. He was suffering badly from shock, but he managed to tell us enough to interest us in this Li Chang Yen. He described four people—the Big Four—an organisation hitherto undreamed of. Number One is Li Chang Yen, Number Two is an unknown American, Number Three an equally unknown Frenchwoman, Number Four may be called the executive of the organisation—the destroyer. My informant died. Tell me, monsieur, is that phrase known to you at all? The Big Four."