In the novel A Murder is Announced, Mrs Swettenham lives in Chipping Cleghorn with her son Edmund, on whom she dotes. She has blue eyes, and a head of little grey curls. Diana Harmon claims that it is a wig.
When she was a child her mother had three servants, but not a kitchen maid. Her mother had felt that this was a sign of them being poor. Later, when Mrs Swettenham and her husband lived in India, they had eighteen servants, as well as an ayah for Edmund. They later lived in Hong Kong.
She once had a Cocker Spaniel named Susie.
In the ITV 2005 adaptation of the novel, Mrs Swettenham is played by Cherie Lunghi. In this adaptation, her first name is Sadie. Her first name is not mentioned in the novel or the 1985 adaptation. In this adaptation, there is also a romantic side plot involving Colonel Easterbrook and Mrs Swettenham. Colonel Easterbrook presents her with a vegetable marrow, and she gives him a basket of quinces.
Mrs Swettenham said that her son, Edmund, was jealous and possessive of her, and did not want her to develop a romantic relationship. This led Edmund to tell the police that the gun used to kill Rudi Scherz belonged to Colonel Easterbrook.
Mrs Swettenham admitted that she had stolen a leg of lamb from Little Paddocks, because she wanted to give Colonel Easterbrook a treat. It had been Mitzi's day off, but she was almost caught because Miss Blacklock came home early. Miss Blacklock had come home to oil the hinges of the second door in the drawing room, and Mrs Swettenham became an inadvertent witness to this.
At the end of the movie, Mrs Swettenham and Colonel Easterbrook walk off arm in arm.