Lunch was a silent meal, and the atmosphere was not a little constrained. Nobody liked to mention the subject which was uppermost in the minds of all; and to speak of anything else seemed out of place. What little conversation there was concerned only the questions of packing and trains. Mrs. Plant, who appeared a little late for the meal but seemed altogether to have regained her mental poise after her strange behaviour in the morning, was to leave a little after five. This would give her time, she explained, to wait for the safe to be opened so that she could recover her jewels. Roger, pondering furiously over the matter-of-fact air with which she made this statement and trying to reconcile it with the conclusions at which he had already arrived regarding her, was forced to admit himself completely at sea again, in this respect at any rate.

And this was not the only thing that perplexed him. Major Jefferson, who had appeared during the earlier part of the morning subdued to the point of gloominess, now wore an air of quiet satisfaction which Roger found extremely difficult to explain. Assuming that Jefferson had been extremely anxious that the police should not be the first persons to open the safe—and that was the only conclusion which Roger could draw from what had already transpired—what could have occurred in the meantime to have raised his spirits to this extent? Visions of duplicate keys and opportunities in the empty library which he himself ought to have been on hand to prevent, flashed, in rapid succession, across Roger’s mind. Yet the only possible time in which he had not been either inside the library or overlooking it were the very few minutes while he was washing his hands upstairs before lunch; and it seemed hardly probable that Jefferson would have had the nerve to utilise them in order to carry out what was in effect a minor burglary, and that with the possibility of being interrupted at any minute. It is true that he had come in very late for lunch (several minutes after Mrs. Plant, in fact); but Roger could not think this theory in the least degree probable.

Yet the remarkable fact remained that the two persons who appeared to have been most concerned about the safe and its puzzling contents were now not only not in the least concerned at the prospect of its immediate official opening, but actually quietly jubilant. Or so, at any rate, it seemed to the baffled Roger. Taking it all round, Roger was not sorry that lunch was such a quiet meal. He found that he had quite a lot of thinking to do.

In this respect he was no less busy when lunch was over. Alec disappeared directly after the meal, and as Barbara disappeared at the same time, Roger was glad to find one problem at least that did not seem to be beyond the scope of his deductive powers. He solved it with some satisfaction and, by looking at his watch, was able to arrive at the conclusion that he would have at least half an hour to himself before his fellow-sleuth would be ready for the trail again. Somewhat thankfully he betook himself to the friendly cedar once more, and lit his pipe preparatory to embarking upon the most concentrated spell of hard thinking he had ever faced in his life.

For in spite of the confidence he had shown to Alec, Roger was in reality groping entirely in the dark. The suggestion of murder, which he had advanced with such assurance, had appeared to him at the time not a little far-fetched; and the fact that he had put it forward at all was due as much as anything to the overwhelming desire to startle the stolid Alec out of some of his complacency. Several times Roger had found himself on the verge of becoming really exasperated with Alec that morning. He was not usually so slow in the uptake, almost dull, as he had been in this affair; yet just now, when Roger was secretly not a little pleased with himself, all he had done was to throw cold water upon everything. It was a useful check to his own exuberance, no doubt; but Roger could wish that his audience, limited by necessity to so small a number, had been a somewhat more appreciative one.

His thoughts returned to the question of murder. Was it so far-fetched, after all? He had been faintly suspicious even before his discovery of the broken vase and that mysterious second shot. Now he was very much more so. Only suspicious, it is true; there was no room as yet for conviction. But suspicion was very strong.

He tried to picture the scene that might have taken place in the library. Old Stanworth, sitting at his table with, possibly, the French windows open, suddenly surprised by the entrance of some unexpected visitor. The visitor either demands money or attacks at once. Stanworth whips a revolver out of the drawer at his side and fires, missing the intruder but hitting the vase. And then—what?

Presumably the two would close then and fight it out in silence. But there had been no signs of a struggle when they broke in, nothing but that still figure lying so calmly in his chair. Still, did that matter very much? If the unknown could collect those fragments of vase so carefully in order to conceal any trace of his presence, he could presumably clear away any evidence of a struggle. But before that there was that blank wall to be surmounted—how did the struggle end?

Roger closed his eyes and gave his imagination full rein. He saw Stanworth, the revolver still in his hand, swaying backwards and forwards in the grip of his adversary. He saw the latter (a big powerful man, as he pictured him) clasp Stanworth’s wrist to prevent him pointing the revolver at himself. There had been a scratch on the dead man’s wrist, now he came to think of it; could this be how he had acquired it? He saw the intruder’s other hand dart to his pocket and pull out his own revolver. And then——!

Roger slapped his knee in his excitement. Then, of course, the unknown had simply clapped his revolver to Stanworth’s forehead and pulled the trigger!