A commonplace killing

"London, July 1946. A woman's body is found in a bomb site off the Holloway Road. She is identified as Lillian Frobisher, "a respectable wife and mother" who lived with her family nearby. The police assume that Lillian must have been the victim of a sexual assault; but when the autopsy finds no evidence of rape, they turn their attention to her private life. How did she come to be in the bomb site...