Poirot's face grew very grave.
"It is a duel to the death, mon ami. You and I on the one side, the Big Four on the other. They have won the first trick; but they have failed in their plan to get me out of the way, and in the future they have to reckon with Hercule Poirot!"
3. WE HEAR MORE ABOUT LI CHANG YEN
For a day or two after our visit from the fake Asylum attendant I was in some hopes that he might return, and I refused to leave the flat even for a moment. As far as I could see, he had no reason to suspect that we had penetrated his disguise. He might, I thought, return and try to remove the body, but Poirot scoffed at my reasoning.
"Mon ami," he said, "if you wish you may wait in to put salt on the little bird's tail, but for me I do not waste my time so."
"Well then, Poirot," I argued, "why did he run the risk of coming at all. If he intended to return later for the body, I can see some point in his visit. He would at least be removing the evidence against himself; as it is, he does not seem to have gained anything."
Poirot shrugged his most Gallic shrug. "But you do not see with the eyes of Number Four, Hastings," he said. "You talk of evidence, but what evidence have we against him? True, we have a body, but we have no proof even that the man was murdered—prussic acid, when inhaled, leaves no trace. Again, we can find no one who saw any one enter the flat during our absence, and we have found out nothing about the movements of our late friend, Mayerling....
"No, Hastings, Number Four has left no trace, and he knows it. His visit we may call a reconnaissance. Perhaps he wanted to make quite sure that Mayerling was dead, but more likely, I think, he came to see Hercule Poirot, and to have speech with the adversary whom alone he must fear."
Poirot's reasoning appeared to me typically egotistical, but I forbore to argue.
"And what about the inquest?" I asked. "I suppose you will explain things clearly there, and let the police have a full description of Number Four."