“I do not know. I am all in the dark. And my uncle, he will not trust me. It is natural, perhaps. You see, he hardly knows me. He saw me as a child, and not since till I came to live with him here in London. But this much I do know, he is in fear of something. We have many secret societies in Russia, and one day I overheard something which made me think it was of just such a society he went in fear. Tell me, monsieur”⁠—she came a step nearer, and dropped her voice⁠—“have you ever heard of a society called the ‘Big Four’?”

Poirot jumped nearly out of his skin. His eyes positively bulged with astonishment.

“Why do you⁠—what do you know of the Big Four, mademoiselle?”

“There is such an association, then! I overheard a reference to them, and asked my uncle about it afterwards. Never have I seen a man so afraid. He turned all white and shaking. He was in fear of them, monsieur, in great fear, I am sure of it. And, by mistake, they killed the American, Wilson.”