As he seated himself near me and began to chat, I realised that he was just as clever and refined as his alleged sister. He had just returned from six months in Russia and the Caucasus, he told me, and described the pleasant time he had had. When at last Mrs Olliffe's visitors rose and left, I requested a word with her alone. "Certainly," she said--not, however, without a slightly startled glance, which I did not fail to notice. "Come in here;" and she led me through to her own little sitting-room--a charming, cosy place, very tastefully furnished and restful. When we were seated, I began without preamble-- "You will recollect, Mrs Olliffe, that we had some conversation concerning the late Melvill Arnold. You were anxious to learn facts connected with his death." "Yes," she said, with a strange look upon her handsome face. "My object, I may as well tell you, Mr Kemball, was to satisfy myself that he died a natural death; that--well, that he was not the victim of foul play." "Foul play!" I gasped, staring at her. "Do you suspect that?" She shrugged her well-shaped shoulders without replying. "Had he any enemies--any person who would benefit by his death?" I asked quickly. "Yes." "And you suspect them of--" "I suspect nobody," she hastened to assure me. "Only his sudden and mysterious end is extremely suspicious." "Well, I can assure you that you need have no suspicion," I said. "I was with him on board ship when he was suddenly taken ill, and I remained with him nearly the whole time until the end." "Nearly. You were absent sometimes." "Of course. I was not with him both night and day." "And therefore you can't say with absolute certainty that his enemies had no access to him," she said. "But even if they had, they can have profited nothing," I said. "How do you know? Melvill Arnold was extremely wealthy. Where is it all? Who knows but that he was not robbed of it in secret, and death brought upon him in order to prevent the truth from being revealed." I shook my head and smiled. "I fear, Mrs Olliffe, that your imagination has run just a trifle wild. Arnold died a natural death, and the doctor gave a certificate to that effect." "I'll never believe it," she declared. "If there had not been foul play, the whereabouts of his great wealth would be known. He was a friend, a great friend, of mine, Mr Kemball, so please forgive me for speaking quite frankly." "You are, of course, welcome to your own opinions, but I, who know the facts so well, and who was present at his death, am able to state with authority that his end was due to natural causes." "It is curious that he should have trusted you--a perfect stranger," she said, with coolness. "You did not explain the nature of your trust." "It was upon that very point, Mrs Olliffe, that I called to see you to-day," I said. "Mr Arnold gave me a letter addressed to a certain Mr Alfred Dawnay, and--"