Mercy by Baldacci David

THE HUNT IS FINALLY OVER. FBI agent Atlee Pine is at the end of her long journey to discover what happened to her twin sister, Mercy, who was abducted when the girls were just six years old – an incident which destroyed her family and left Atlee physically and mentally scarred. She knew her sister and parents were out there somewhere. And she had to find them. Dead or alive. Atlee and her assistant, Carol Blum, discover the truth. But the truth hurts. And hurt makes you tough. So how tough do you have to be to forgive? As they uncover a shocking trail of lies, greed, fear and revenge, they must face one final challenge. A challenge more deadly and dangerous than they could ever have imagined.