Miss Lingard

In the novella Dead Man's Mirror, Miss Lingard was the research assistant of Gervase Chevenix-Gore. She took up the position some two months before the events in the novella when Gervase needed help researching and writing up his family history.

Miss Lingard later confessed to the murder of Gervase. It turned out that she had had an affair with Anthony Chevenix-Gore, Gervase's brother. They had a daughter Ruth Chevenix-Gore. When Anthony died, Ruth was adopted by Gervase and his wife. As research assistant, Miss Lingard was familiar with Gervase's papers. She found out that Gervase planned a new will which would have disinherited Ruth unless she married Hugo Trent whom she did not wish to. Not wanting to let Gervase destroy Ruth's happiness, Miss Lingard killed him before he could sign the new will.

Portrayals
Miss Lingard is played by Fiona Walker in the film adaptation of the original story in Series 5 of ITV's Agatha Christie's Poirot. Her portrayal is fairly close to the original except that in the film, she was helping Gervase conduct research in modern art and not about is family history. In the original story, she confessed to the crime when she saw that Poirot was sealing a case against her daughter Ruth. In the film she tried to manipulate Vanda Chevenix-Gore into signing a confession by imitating the voice of "Safra" a figure from ancient Egypt who Vanda regarded as her spirit guide.