P.D. James 
Innocent Blood 

Adopted as a child into a privileged family, Philippa Palfrey fantasizes that she is the daughter of an aristocrat and a parlor maid. The terrifying truth about her parents and a long-ago murder is only the first in a series of shocking betrayals. Philippa quickly learns that those who delve into the secrets of the past must be on guard when long-buried horrors begin to stir."As a crime novel, " wrote the London Times, Innocent Blood is "the peak of the art." "Flawlessly crafted…profoundly, masterfully moving, " Cosmopolitan concurred.