The Hunter - John Lescroart

Raised by loving adoptive parents, San Francisco private investigator Wyatt Hunt never had an interest in finding his birth family-until he gets a chilling text message:

"How did your mother die?"

The answer is murder, and Hunt takes on a case he never knew existed, unsolved for decades. His family's dark past unfurls in dead ends. Child Protection Services, who suspected Hunt was being neglected, is uninformed; his birth father, twice-tried but never convicted of the murder, is in hiding; Evie, his mother's drug-addicted religious fanatic of a friend, is untraceable. And who is the texter, and how is this person connected to Hunt? Time is running out. Insisting the murderer is out there, the texter refuses to be identified. But as the case escalates, so does the threat-for the killer has a secret that will go to the grave.