Killer Instinct

"Killer Instinct" is the second novel in Jennifer Lynn Barnes's young-adult crime thriller series The Naturals, following seventeen-year-old Cassie Hobbes, a gifted profiler recruited into a classified FBI program that pairs teenagers who have innate crime-solving talents with cold cases. After barely surviving a confrontation with a killer obsessed with her mother's murder, Cassie hopes the team can go back to working cases from a safe distance. That changes when a brutal new serial killer begins leaving victims behind, and the Naturals are pulled into an active investigation that strikes uncomfortably close to home: the murderer is a perfect copycat of Dean Redding's incarcerated father, a man Dean would do anything to forget.

Like the rest of the series, the book builds its suspense around the idea of profiling and getting inside a killer's mind, forcing the young team deeper into a murderer's psychology than ever before. Alongside the central copycat case, the novel keeps its focus on the friendships and rivalries among the recruits and on the emotional cost of Dean confronting his family's violent legacy, while Cassie and the others try to stay a step ahead of the killer's mind games.

Barnes, who holds a background in cognitive science and psychology, uses that expertise to ground the series' portrayal of behavioral profiling. The Naturals grew into a popular multi-book series and helped establish Barnes's reputation for twisty thrillers, a reputation she later expanded with the best-selling The Inheritance Games.