God Save The Child by Robert B. Parker

In this gripping mystery, private investigator Spenser is hired to find a missing teenager, Kevin Bartlett, who has vanished from his suburban home in Massachusetts. As Spenser delves into the case, he uncovers a web of family secrets, deceit, and unexpected twists that challenge his detective skills and moral compass. The investigation takes him through a maze of suspects, including Kevin's dysfunctional family, a shady psychiatrist, and a mysterious bodybuilder, leading to a tense and surprising climax that tests Spenser's resolve and ingenuity.