In the novel One, Two, Buckle My Shoe, Agnes Fletcher is the house parlourmaid of the Morley's at 58 Queen Charlotte Street. After the death of Henry Morley, his Georgina moved to live in Hertford. Agnes followed and continued in service with her and reportedly became a good cook.
Late in the novel, Agnes wrote to Poirot to say that she had something to tell him about the circumstances of Mr Morley's death. Subsequently, at a meeting in a teashop at Hertford, she met Poirot and told him that around the time Morley was believed to have been killed, she saw Frank Carter on the stairs just outside his office. At the time she had discussed this with Emma the cook and they had agreed not to mention this to the police as they did not want to get him in trouble since he was the boyfriend of Gladys Nevill.
Agnes prefaced her report to Poirot with a blameless family history--how her father, a proprietor of licensed premises, "had never once had any friction with the police, closing time being strictly observed to the second". Her father and mother were respected in her hometown of Little Darlingham, Gloucestershire. She was from a family of six who had never given their parents any trouble. So telling Poirot about Carter was a source of great anxiety for her since her mother might not approve of her getting involved with the police. Poirot however assured her that she had done the right thing.