Letitia “Letty” Blacklock is the name used by the owner of Little Paddocks in Chipping Cleghorn. She is about sixty years of age, and is tall, and active-looking. She has "keen grey eyes and a square determined chin", and grey hair with a slight natural wave.
This legacy is presumed to be the motive behind an attempt on Miss Blacklock's life in A Murder is Announced. It is later revealed that the person claiming to be Letitia Blacklock was really Charlotte Blacklock, Letitia's sister. The real Letitia had died in Switzerland, and Charlotte had posed as her sister in order to inherit Randall Goedler's fortune after his wife died.
In the ITV 2005 adaptation of the novel, Letitia Blacklock is played by Zoë Wanamaker. In this adaptation, she has a nightmare about the shooting at Little Paddocks, and the dead body of Rudi Scherz, with blood on his face. Her screams wake the rest of the household, and Dora Bunner comforts her. On Miss Bunner's birthday, Miss Blacklock gives her own earrings to Miss Bunner to wear. At the end of the movie, Miss Blacklock shows remorse for Miss Bunner's death, repeatedly saying, "I'm sorry, Bunny." She then briefly sees Miss Bunner's "ghost" through the open door of the drawing room.