“ Mon ami ,” said Poirot, “you make one error. You do not allow for the fact that a man who had decided to make away with another man⁠—or with himself in a figurative sense⁠—might be that rare machine, a man of method. He might bring intelligence, talent, a careful calculation of detail to the task; and then I do not see why he should not be successful in baffling the police force.”

“But not you , I suppose?” said Japp good-humouredly, winking at me. “He couldn’t baffle you , eh, Monsieur Poirot?”

Poirot endeavoured, with a marked lack of success, to look modest. “Me, also! Why not? It is true that I approach such problems with an exact science, a mathematical precision, which seems, alas, only too rare in the new generation of detectives!”

Japp grinned more widely.