Janet (The Body in the Library)

In the novel The Body in the Library, Janet is mentioned by Miss Marple. Janet was a former maid of Miss Marple's. She used to give herself away when she was lying, by relaxing too soon. She would explain quite convincingly that mice had eaten the end of a cake, but would give herself away by smirking as she left the room. Miss Marple said that Florence Small had done the same thing after talking to Detective Superintendent Harper and herself.