The Cater Street Hangman

Really super crime detective book, first in the series about Thomas and Charlotte Pitt. It's set in the late 1800's. Charlotte is still at home with her upper middle class family. Pitt is a policeman and meets Charlotte during the investigation into strangling deaths of young women in her neighborhood, including her elder sister Sarah. It's partly a love story - Charlotte forced by her own intelligence and honesty to see Pitt not as an irritating, presumptuous lower-class person but as a man, himself intelligent, gentle and fiercely dedicated to finding the truth in the murder investigations. Charlotte with her entree into and knowledge of society and Pitt with his street smarts solve the murders together.