In the novel 4.50 from Paddington, Louisa Felby is mentioned by Miss Marple. Miss Marple says that Louisa came to see her once, and had to ask to go upstairs five times during a period of half an hour, because she had eaten a bad Cornish pasty. Miss Marple mentions this because part of her plan for proving the identity of the murderer involves Elspeth McGillicuddy going to Rutherford Hall, and asking to go upstairs, and Mrs McGillicuddy feels that this seems very odd.
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