Once gone
(Book)

Publication information from Amazon.com.

"Women are turning up dead in the rural outskirts of Virginia, killed in grotesque ways, and when the FBI is called in, they are stumped. A serial killer is out there, his frequency increasing, and they know there is only one agent good enough to crack this case: Special Agent Riley Paige. Riley is on paid leave herself, recovering from her encounter with her last serial killer, and, fragile as she is, the FBI is reluctant to tap her brilliant mind. Yet Riley, needing to battle her own demons, comes on board, and her hunt leads her through the disturbing subculture of doll collectors, into the homes of broken families, and into the darkest canals of the killer's mind. As Riley peels back the layers, she realizes she is up against a killer more twisted than she could have imagined. In a frantic race against time, she finds herself pushed to her limit, her job on the line, her own family in danger, and her fragile psyche collapsing. Yet once Riley Paige takes on a case, she will not quit. It obsesses her, leading her to the darkest corners of her own mind, blurring the lines between hunter and hunted. After a series of unexpected twists, her instincts lead her to a shocking climax that even Riley could not have imagined. A dark psychological thriller with heart-pounding suspense." --,(Source of summary not specified)