“Well, my dear, it would seem that we have three people who had, or might have thought they had, a motive to kill the old lady. And three quite simple reasons why none of the three could have done so. The housekeeper could not have done so because she was locked in her room and because Miss Greenshaw definitely stated that a man shot her. The gardener could not have done it because he was inside the Dog and Duck at the time the murder was committed, the nephew could not have done it because he was still some distance away in his car at the time of the murder.”

“Very clearly put, madam,” said the inspector.

“And since it seems most unlikely that any outsider should have done it, where, then, are we?”

“That’s what the inspector wants to know,” said Raymond 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.