He led the way out of the room, paused a moment as though considering, and then walked down to the end of the corridor, stopping outside the small den where the chambermaids and valets of the respective floors congregated. Our particular chambermaid appeared to be holding a small court there, and to be retailing her late experiences to an appreciative audience. She stopped in the middle of a sentence. Poirot bowed with his usual politeness.

“Excuse that I derange you, but I shall be obliged if you will unlock for me the door of Mr. Opalsen’s room.”

The woman rose willingly, and we accompanied her down the passage again. Mr. Opalsen’s room was on the other side of the corridor, its door facing that of his wife’s room. The chambermaid unlocked it with her passkey, and we entered.

As she was about to depart Poirot detained her.