"Well, I don't know, sir, I expect she would lock it up in that
purple case of hers."

"Is that where she usually kept important papers?"

"Yes, sir. She brought it down with her every morning, and took
it up every night."

"When did she lose the key of it?"

"She missed it yesterday at lunch-time, sir, and told me to look
carefully for it. She was very much put out about it."

"But she had a duplicate key?"

"Oh, yes, sir."

Dorcas was looking very curiously at him and, to tell the truth,
so was I. What was all this about a lost key? Poirot smiled.

"Never mind, Dorcas, it is my business to know things. Is this
the key that was lost?" He drew from his pocket the key that he
had found in the lock of the despatch-case upstairs.

Dorcas's eyes looked as though they would pop out of her head.

"That's it, sir, right enough. But where did you find it? I
looked everywhere for it."

"Ah, but you see it was not in the same place yesterday as it was