Sylvia Dering

In the novel The Sittaford Mystery, Mrs Sylvia Dering (née Pearson) is Captain Trevelyan's niece and the sister of James and Brian Pearson. She is married to Martin Dering. Sylvia lives with her husband in Wimbledon, London, at a house named "The Nook" on Surrey Road.

As one of the beneficiaries of her uncle's will, and as someone who knew the terms of the legacy, Sylvia became a natural suspect of the murder of Captain Trevelyan. However she had an alibi for the time in question. She had played bridge all that afternoon and a friend came in and spent the evening with her. Her husband was out for a literary dinner.

Inspector Narracott observed that Sylvia was only twenty-five but looked considerably over thirty. "She was small and fair and anemic looking, with a worried and harassed expression." Inspector Narracott found that Sylvia had a faintly complaining note in her voice and that is "about the most annoying sound a human voice can contain". There are hints that Sylvia's relationship with Martin Dering is strained. Edgar Rosenkraun, Martin Dering's publisher, agreed to lie for him to give him an alibi. He later admitted that he had agreed to alibi Dering as a favour from one friend to another because he believed Sylvia was having Martin watched in preparation for divorce proceedings.