My friend smiled and shook his head.

“I play the game for the game’s own sake,” said he. “But the problem certainly presents some points of interest, and I shall be very pleased to look into it. Some more facts, please.”

“I have jotted down the more essential ones upon this sheet of paper, together with a few addresses which you will find of service. The actual official guardian of the papers is the famous government expert, Sir James Walter, whose decorations and sub-titles fill two lines of a book of reference. He has grown gray in the service, is a gentleman, a favoured guest in the most exalted houses, and, above all, a man whose patriotism is beyond suspicion. He is one of two who have a key of the safe. I may add that the papers were undoubtedly in the office during working hours on Monday, and that Sir James left for London about three o’clock taking his key with him. He was at the house of Admiral Sinclair at Barclay Square during the whole of the evening when this incident occurred.”

“Has the fact been verified?”