Lancaster groaned helplessly. "Trouble upon trouble! But I cannot face another visit to Christopher's house—"
"Be easy. You shall be spared that. I think I had better tell you nothing for the present—except that I may take a run over to Paris within the next few days."
"Paris!"
"You can say I'm there if any one asks."
Lancaster drew his hand across his brow. "Sometimes," he said slowly, "I wish I were at peace—in jail."
"Don't be a fool! You'll feel differently when we open the Green Box."
The other shook his head. "There's another point that has worried me horribly. We have thought we were the only persons outside of Grey House who knew of the diamonds; but who was the person who took the box that night? Whoever he was he must have seen us and heard something of our talk."
"Yes," said Bullard, with a short laugh, "it seems very dreadful and mysterious, doesn't it?—especially as Caw recovered the diamonds so speedily. I've thought it out, Lancaster, and I've struck only one reasonable conclusion. There was no fourth person present that night. Caw was fooling us all the time. The cupboard is really a passage to another room, made for old Christopher's convenience, no doubt. How's that?"
"Caw acted well, if he were acting. And why should he have suspected us at all?"
"Simply because he happened to know what was in the box. Who would trust a fellow creature alone with £600,000 in a portable form? And Caw was probably in the position of guardian. Have you a better theory?"