A wrongful death / Kate Wilhelm.

Enhanced descriptions from Syndetics:

Who knew that being aGood Samaritan would leadBarbara Holloway to face her biggestchallenge ever: being named primesuspect in a high-profile kidnapping?

The peace and quiet of Barbara's retreat onthe Oregon coast is shattered when a terrifiedyoung boy calls to her as she walks along adeserted beach. Frantically he leads her to acabin deep in the woods where his motherlies senseless and battered--clearly left fordead. Barbara runs for help, but by the timeshe returns with the police and medics bothmother and son are gone.

The puzzle only deepens when, back in thecity, Barbara learns that the boy she met is thegrandson of a wealthy and prominent family--and that they have accused her of aiding andabetting his disappearance.

With the help of her father, Frank, Barbaradelves into the mystery of the missing child,only to realize that the kidnapping is a ruse fora more sinister plan--a plan that pits themeaning of family against cold hard cash.

But the more she learns, the more questionsshe has, and troubling obstacles continue tothwart her every move--from the justice systemthat employs her, to the false identities of thosearound her. Yet none of these things comparesto the shocking murder scene that awaits her.