Enemy Within — Christiane Heggan

Thirty years ago, a woman accused of murdering her husband placed her newborn daughter on a convent's steps, then staged her own death. She leaves behind a mystery that would return three decades later to rock a family...

When Rachel Spaulding inherits her family's Napa Valley vineyard, it's a dream come true for the adopted daughter of loving parents. But her legacy is greeted with bitter hatred by her sister, Annie, who vows to do whatever it takes to discredit Rachel and claim the Spaulding vineyards for herself. And Annie begins by hiring a detective to dig into Rachel's past.

This was supposed to be a routine investigation, but Et. Gregory Shaw realizes too late he's been used. When the information he uncovers for Annie leads to the reopening of a sensational murder case, he can't walk away. Especially when he feels responsible for the pain it's causing Rachel Spaulding.

But even Gregory is unaware of the danger emerging from three decades of deceit. And even he can't recognize the enemy within who knows there is only one way to lock the door of the past forever. Murder.