Killer Instinct

Overview

"Killer Instinct" continues Jennifer Lynn Barnes's series about the Naturals, a covert FBI program that recruits teenagers with uncanny instincts for reading people. Cassie Hobbes, whose gift for profiling has already pulled her into one deadly confrontation tied to her mother's death, hopes for a quieter stretch working cold cases alongside her fellow recruits. That hope collapses when a new killer begins staging crime scenes that echo, in exacting detail, the methods of a notorious murderer already behind bars: the father of teammate Dean, a man whose legacy Dean has spent years trying to outrun.

As the copycat's pattern escalates, the team is drawn away from the safety of historical analysis and into an active, unfolding investigation. Barnes uses the premise to push her young profilers past intellectual puzzle-solving into something more unsettling: understanding a killer well enough to anticipate him means understanding how much of his mindset might already live in someone they care about.

The novel keeps the series' emphasis on procedural detail and psychological deduction, filtering an adult crime-thriller structure through the perspective of teenagers who are still learning what their abilities cost them.

A Second Look at the Naturals Series

Barnes, better known to many readers for "The Inheritance Games," built the Naturals books around a premise that borrows heavily from adult crime procedurals while keeping its cast and emotional stakes firmly teenage. That hybrid identity is part of what makes the series distinctive: it treats its young characters as capable of the same analytical rigor as trained profilers, while still tracking the ordinary adolescent fallout of trauma, found-family bonds, and first loves.

"Killer Instinct" sharpens that tension by making the case personal rather than academic. Dean's connection to the killer being studied forces the book to ask what a young person owes to a parent's legacy, and whether proximity to violence can be studied clinically or always leaves a mark. The series has sustained a devoted YA readership precisely because it takes these questions seriously rather than using them as backdrop for a straightforward mystery.

Why Killer Instinct Has Been Challenged

A parent objection lodged against the book centered on the idea that its teenage characters are shown analyzing a serial killer's methods and motivations in clinical, almost admiring detail, which the complaint framed as inappropriate material to place in front of adolescent readers regardless of the fictional frame. Other criticism has focused more broadly on the book's violent content: descriptions of crime scenes, the psychological manipulation the killer inflicts on his pursuers, and the general darkness of a plot built around a copycat murderer targeting minors. Some challenges to the series have also pointed to its treatment of trauma and grief as too heavy for the intended age group, arguing that a program premised on recruiting traumatized teenagers to relive violent crime normalizes exposure to disturbing material. Records show the book has been challenged in 1 state and 1 school district within the scope of this catalog, with objections concentrated on its violent and psychologically intense subject matter rather than on language or sexual content.