Thriller by Lisa Gardner: a disappearance and secrets

When Frankie Elkin wants to join a group of volunteers going in search of Timothy O’Day, a young man who disappeared in the forests of Wyoming five years earlier, she is not exactly well received. Everyone there knows their stuff and has a good reason to get into this business. First, Timothy’s loved ones: Martin O’Day, his father, and the four friends with whom he had embarked on a hike to celebrate his bachelor’s party. Five years later, consumed by guilt, they followed their friend’s father who seemed to have forced their hand a little.