"Will she be able to do so?"
"The Lord only knows. There's one thing, Inglethorp himself won't be too keen on meeting her."
"You've got the keys still, haven't you, Poirot?" I asked, as we reached the door of the locked room.
Taking the keys from Poirot, John unlocked it, and we all passed in. The lawyer went straight to the desk, and John followed him.
"My mother kept most of her important papers in this despatch-case, I believe," he said.
Poirot drew out the small bunch of keys.
"Permit me. I locked it, out of precaution, this morning."
"But it's not locked now."
"Impossible!"
"See." And John lifted the lid as he spoke.
"Milles tonnerres!" cried Poirot, dumfounded. "And I--who have both the keys in my pocket!" He flung himself upon the case. Suddenly he stiffened. "En voila une affaire! This lock has been forced."
"What?"
Poirot laid down the case again.
"But who forced it? Why should they? When? But the door was locked?" These exclamations burst from us disjointedly.
Poirot answered them categorically--almost mechanically.
"Who? That is the question. Why? Ah, if I only knew. When? Since I was here an hour ago. As to the door being locked, it is a very ordinary lock. Probably any other of the doorkeys in this passage would fit it."
We stared at one another blankly. Poirot had walked over to the mantel-piece. He was outwardly calm, but I noticed his hands, which from long force of habit were mechanically straightening the spill vases on the mantel-piece, were shaking violently.
"See here, it was like this," he said at last. "There was something in that case--some piece of evidence, slight in itself perhaps, but still enough of a clue to connect the murderer with the crime. It was vital to him that it should be destroyed before it was discovered and its significance appreciated. Therefore, he took the risk, the great risk, of coming in here. Finding the case locked, he was obliged to force it, thus betraying his presence. For him to take that risk, it must have been something of great importance."
"But what was it?"
"Ah!" cried Poirot, with a gesture of anger. "That, I do not know! A document of some kind, without doubt, possibly the scrap of paper Dorcas saw in her hand yesterday afternoon. And I--" his anger burst forth freely--"miserable animal that I am! I guessed nothing! I have behaved like an imbecile! I should never have left that case here. I should have carried it away with me. Ah, triple pig! And now it is gone. It is destroyed--but is it destroyed? Is there not yet a chance--we must leave no stone unturned--"