"Well," I asked, after he was out of hearing, "what do you intend doing now?" "I never set out any line of action. In such a case as this any such method is folly," he replied. "But at least you will do something with the bodies of the victims? They must be buried," I exclaimed, for the gruesomeness of it all was now preying upon me. This was the first time that I had ever been implicated in a murder mystery--_and such a mystery_! "The disposal of the bodies is my own affair, Mr. Holford," he said quietly. "Leave that to me. As far as the world knows, Professor Greer and his daughter are away visiting." "But Lady Mellor! Is she not anxious regarding her niece's whereabouts?" "Lady Mellor is on the Riviera. Her house in Upper Brook Street is in charge of servants, therefore she is unaware that anything extraordinary has transpired." "Your only confidant is Antonio?" "And your own self," he added. "But have I not already impressed upon you, my dear friend, the absolute necessity of secrecy in this affair?" "You have given me no actual reason," I demurred. "Because certain circumstances bind me to secrecy," was his reply. "From what I have already told you I dare say you have gathered that I am no ordinary individual. I am vested by a high authority with a power which other men do not possess, and in this case I am compelled to exercise it." He saw the look of disbelief upon my countenance. "Ah," he laughed, "I see you doubt me! Well, I am not surprised; I should do so were I in your place. But, believe me or not, Mr. Holford, you will lose nothing, by assisting me in this affair and performing a secret service for the high authority who must be nameless, but whose trusted agent I am--even though the onus of this strange tragedy may be cast upon me." "The whole affair is a mystery," I remarked--"an inscrutable mystery." "Yes," he sighed, "one that has been rendered a hundredfold more inscrutable by a discovery made to-day--the discovery which prevented me calling upon you at eleven o'clock. But remain patient, trust in me, assist me when I desire assistance, and it will, I promise, be well worth your while." For a moment I was silent. Then, a trifle annoyed, I answered: "My legitimate profession of motor-engineer pays me quite well, and I think I prefer, with your permission, to retire from this affair altogether." "What!" he exclaimed. "After giving me your promise--your word as a gentleman! Can't you see, my friend, that you can assist in furthering the ends of justice--in fastening the guilt upon the assassin?" "That, I maintain, should be left to the police." "Bah! The police in this case would be powerless. The problem is for us, you and I, to solve, and by the exercise of patience and watchfulness we shall, I hope, be able to elucidate the mystery.