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."
"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."
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. P