It was at that moment that I knocked down the rack that held my pieces. My sister immediately reproved me for clumsiness, but half-heartedly. She was intent on her theory.

“Cranchester, Miss Caroline?” said Colonel Carter. “Surely not Cranchester! It’s so near.”

“That’s exactly it,” cried Caroline triumphantly. “It seems quite clear by now that he didn’t get away from here by train. He must simply have walked into Cranchester. And I believe he’s there still. No one would dream of his being so near at hand.”

I pointed out several objections to the theory, but when once Caroline has got something firmly into her head, nothing dislodges it.

“And you think M. Poirot has the same idea,” said Miss Gannett thoughtfully. “It’s a curious coincidence, but I was out for a walk this afternoon on the Cranchester road, and he passed me in a car coming from that direction.”