"But delay may result in the catastrophe," I said. "The yacht may sail at any moment when it pleases her owner to cast her away."
"Well," he said, after a few moments of hesitation, "what you have told me certainly increases the mystery, and is deeply interesting. You have, I suppose, no suspicion that any of the yacht's officers are aware of the plot?"
"The unseen originator of the conspiracy may have been an officer, for aught I know," I said. "I have related the occurrence to you just as it took place. I know exactly nothing more."
"But you must discover more," he declared anxiously. "The matter must not rest here. If what you say is really true, then there has been murder done on board. The mysterious passenger is a perplexing feature, to say the least. Describe her to me as fully as you can."
I acted upon his suggestion. Unfortunately, however, suspended as I had been in that tearing wind on the night of my discovery, I had been unable to take in every detail of her features. But I gave him a description as minute as was possible, and it apparently satisfied him.
"Strange," he murmured, "very strange! To me it seems as though your discovery leads us into an entirely different channel of inquiry. Surely Keppel himself had nothing to do with the assassination of young Signor Thorne!" he added slowly, as though the startling theory only that moment occurred to him.
More than once already had that same suspicion crossed my mind, but I had always laughed it to scorn. There was an utter absence of motive, that convinced me of its impossibility.
And yet, had I not actually heard with my own ears Keppel confess to a murder which he himself had committed?
"Do you think that the lady could have come on board at Algiers?" he inquired.
"I cannot tell," was my answer. "The deckhouse has been kept closed and curtained during the whole cruise. It was that fact which aroused my feminine curiosity."