Sleeping Murder by Agatha Christie

case—Halliday was induced to believe that he had killed his wife, by someone else. In other words, we've come to X.'
    'Going over the facts very carefully, I'd say that that hypothesis is at least possible. According to his own account, Halliday came into the house that evening, went into the dining-room, took a drink as he usually did—and then went into the next room, saw a note on the desk and had a blackout—'
    Giles paused and Miss Marple nodded her head in approval. He went on: 'Say it wasn't a blackout—that it was just simply dope—knock-out drops in the whisky. The next step is quite clear, isn't it? X had strangled Helen in the hall, but afterwards he took her upstairs and arranged her artistically as a crime passionel on the bed, and that's where Kelvin is when he comes to; and the poor devil, who may have been suffering from jealousy where she's concerned, thinks that he's done it. What does he do next? Goes off to find his brother-in-law—on the other side of the town and on foot. And that gives X time to do his next trick. Pack and remove a suitcase of clothes and also remove the body—though what he did with the body,' Giles ended vexedly, 'beats me completely.'
    'It surprises me you should say that, Mr Reed,' said Miss Marple. 'I should say that that problem would present few difficulties. But do please go on.'
    'Who Were The Men In Her Life?' quoted Giles. 'I saw that in a newspaper as we came back in the train. It set me wondering, because that's really the crux of the matter, isn't it? If there is an X, as we believe, all we know about him is that he must have been crazy about her—literally crazy about her.'
    'And so he hated my father,' said Gwenda. 'And he wanted him to suffer.'
    'So that's where we come up against it,' said Giles. 'We know what kind of a girl Helen was—' he hesitated.
    'Man mad,' supplied Gwenda.
    Miss Marple looked up suddenly as though to speak, and then stopped.
    '—and that she was beautiful. But we've no clue to what other men there were in her life besides her husband. There may have been any number.'
    Miss Marple shook her head.
    'Hardly that. She was quite young, you know. But you are not quite accurate, Mr Reed. We do know something about what you have termed “the men in her life”. There was the man she was going out to marry—'
    'Ah yes—the lawyer chap? What was his name?'
    'Walter Fane,' said Miss Marple.
    'Yes. But you can't count him. He was out in Malaya or India or somewhere.'
    'But was he? He didn't remain a tea-planter, you know,' Miss Marple pointed out. 'He came back here and went into the firm, and is now the senior partner.'
    Gwenda exclaimed: 'Perhaps he followed her back here?' 'He may have done. We don't know.' Giles was looking curiously at the old lady. 'How did you find all this out?' Miss Marple smiled apologetically.
    'I've been gossiping a little. In shops—and waiting for buses. Old ladies are supposed to be inquisitive. Yes, one can pick up quite a lot of local news.'
    'Walter Fane,’ said Giles thoughtfully. 'Helen turned him down. That may have rankled quite a lot. Did he ever marry?'
    'No,’ said Miss Marple. 'He lives with his mother. I'm going to tea there at the end of the week.'
    'There's someone else we know about, too,’ said Gwenda suddenly. 'You remember there was somebody she got engaged to, or entangled with, when she left school—someone undesirable, Dr Kennedy said. I wonder just why he was undesirable...'
    'That's two men,’ said Giles. 'Either of them may have had a grudge, may have brooded... Perhaps the first young man may have had some unsatisfactory mental history.'
    'Dr Kennedy could tell us that,’ said Gwenda. 'Only it's going to be a little difficult asking him. I mean, it's all very well for me to go along and ask for news of my stepmother whom I barely remember. But it's going to take a bit of explaining if I want to know about her early love-affairs. It seems rather excessive interest in a stepmother