Free Clues to Christie by Agatha Christie

West.
    “One so often looks at a thing the wrong way round,” said Miss Marple apologetically. “If we can’t alter the movements or the position of those three people, then couldn’t we perhaps alter the time of the murder?”
    “You mean that both my watch and the clock were wrong?” asked Lou.
    “No dear,” said Miss Marple, “I didn’t mean that at all. I mean that the murder didn’t occur when you thought it occurred.”
    “But I saw it,” cried Lou.
    “Well, what I have been wondering, my dear, was whether you weren’t meant to see it. I’ve been asking myself, you know, whether that wasn’t the real reason why you were engaged for this job.”
    “What do you mean, Aunt Jane?”
    “Well, dear, it seems odd. Miss Greenshaw did not like spending money, and yet she engaged you and agreed quite willingly to the terms you asked. It seems to me that perhaps you were meant to be there in that library on the first floor, looking out of the window so that you could be the key witness—someone from outside of irreproachable good faith—to fix a definite time and place for the murder.”
    “But you can’t mean,” said Lou, incredulously, “that Miss Greenshaw intended to be murdered.”
    “What I mean, dear,” said Miss Marple, “is that you didn’t really know Miss Greenshaw. There’s no real reason, is there, why the Miss Greenshaw you saw when you went up to the house should be the same Miss Greenshaw that Raymond saw a few days earlier? Oh, yes, I know,” she went on, to prevent Lou’s reply, “she was wearing the peculiar old-fashioned print dress and the strange straw hat, and had unkempt hair. She corresponded exactly to the description Raymond gave us last weekend. But those two women, you know, were much of an age and height and size. The housekeeper, I mean, and Miss Greenshaw.”
    But the housekeeper is fat!” Lou exclaimed. “She’s got an enormous bosom.”
    Miss Marple coughed.
    “But my dear, surely, nowadays I have seen—er—them myself in shops most indelicately displayed. It is very easy for anyone to have a—a bust—of any size and dimension.”
    “What are you trying to say?” demanded Raymond.
    “I was just thinking, dear, that during the two or three days Lou was working there, one woman could have played the two parts. You said yourself, Lou, that you hardly saw the housekeeper, except for the one moment in the morning when she brought you in the tray with coffee. One sees those clever artists on the stage coming in as different characters with only a minute or two to spare, and I am sure the change could have been effected quite easily. That marquise head-dress could be just a wig slipped on and off.”
    “Aunt Jane! Do you mean that Miss Greenshaw was dead before I started work there?”
    “Not dead. Kept under drugs, I should say. A very easy job for an unscrupulous woman like the housekeeper to do. Then she made the arrangements with you and got you to telephone to the nephew to ask him to lunch at a definite time. The only person who would have known that this Miss Greenshaw was not Miss Greenshaw would have been Alfred. And if you remember, the first two days you were working there it was wet, and Miss Greenshaw stayed in the house. Alfred never came into the house because of his feud with the housekeeper. And on the last morning Alfred was in the drive, while Miss Greenshaw was working on the rockery—I’d like to have a look at that rockery.”
    “Do you mean it was Mrs. Cresswell who killed Miss Greenshaw?”
    “I think that after bringing you your coffee, the woman locked the door on you as she went out, carried the unconscious Miss Greenshaw down to the drawing-room, then assumed her ‘Miss Greenshaw’ disguise and went out to work on the rockery where you could see her from the window. In due course she screamed and came staggering to the house clutching an arrow as though it had penetrated her throat. She called for help and was careful to say