“Undoubtedly,” answered Ulrica. “The mystery is inexplicable, but with your aid we must solve it.” “With my aid!” he cried. “I fear I cannot help you. I know nothing whatever about it.” “Of course not,” I said. “But now tell us what is your theory? You were his best friend, and would therefore probably know if he had any enemy who desired to wreak revenge upon him.” “He hadn’t a single enemy in the world, to my knowledge,” Gerald answered. “The motive of the crime was robbery, without a doubt. Most probably he was followed from Monte Carlo by someone who watched his success at the tables. There are always some desperate characters among the crowd there.” “Do you think, then, that the murderer was actually watching us ever since the afternoon?” I inquired in alarm. “I think it most probable,” he responded. “At Monte Carlo there is a crowd of all sorts and conditions of outsiders. Many of them wouldn’t hesitate to commit murder for the sum which poor Reggie had in his pockets.” “It’s terrible!” ejaculated Ulrica. “Yes,” he sighed, whilst his face grew heavy and thoughtful. “This awful news has upset me quite as much as it has you. I have lost my best friend.” “I hope you will spare no effort to clear up the mystery,” I said, for I had rather liked the poor boy ever since chance had first thrown us together in Washington, and on the renewal of our acquaintance a few days previously my estimate of his character and true worth had considerably improved. It was appalling that he should be thus struck down so swiftly and in a manner so strange. “Of course, I shall at once do all I can,” he declared. “I’ll see the police and state all I know. If this had occurred in England or in America there might be a chance of tracing the culprit by the numbers on the bank-notes. In France, however, the numbers are never taken, and stolen notes cannot be recovered. However, rest assured, both of you, that I’ll do my very best.” There was a tap at the door at that moment, and opening it, I was confronted by a tall, dark-bearded Frenchman, who explained that he was an agent of police. To him Gerald related all he knew regarding poor Reggie’s acquaintances and movements while on the Riviera, and afterwards in company with the detective he went to the rooms we had abandoned and there gazed for the last time upon the dead face of his friend. This sudden tragic event had cast a gloom over both Ulrica and myself. We were both nervous and apprehensive, ever debating the mysterious reason which caused Reggie to enter our sitting-room in our absence. Surely he had some very strong motive, or he would not have returned straight there and commenced that mysterious letter of explanation.