The Apprentice: A Rizzoli & Isles Novel

man has is called frontal disinhibition syndrome. The frontal lobes affect our foresight and judgment. Our ability to control inappropriate impulses. If they’re damaged, you become socially disinhibited. You display inappropriate behavior, without any feelings of guilt or emotional pain. You lose the ability to control your violent impulses. And we all have them, those moments of rage, when we want to strike back. Ram our car into someone who’s cut us off in traffic. I’m sure you know what it feels like, Detective. To be so angry you want to hurt someone.”
    Rizzoli said nothing, silenced by the truth of O’Donnell’s words.
    “Society thinks of violent acts as manifestations of evil or immorality. We’re told we have ultimate control over our own behavior, that each and every one of us has the free will to choose
not
to hurt another human being. But it’s not just morality that guides us. Biology does as well. Our frontal lobes help us integrate thoughts and actions. They help us weigh the consequences of those actions. Without such control, we’d give in to every wild impulse. That’s what happened to this man. He lost the ability to control his behavior. He had sexual feelings toward his daughter, so he molested her. His wife made him angry, so he beat her to death. From time to time, we all have disturbing or inappropriate thoughts, however fleeting. We see an attractive stranger, and sex flashes into our heads. That’s all it is—just a brief thought. But what if we gave in to the impulse? What if we couldn’t stop ourselves? That sexual impulse could lead to rape. Or worse.”
    “And that was his defense? ‘My brain made me do it’?”
    Annoyance sparked in O’Donnell’s eyes. “Frontal disinhibition syndrome is an accepted diagnosis among neurologists.”
    “Yeah, but did it work in court?”
    A cold pause. “Our legal system is still working with a nineteenth-century definition of insanity. Is it any wonder the courts are ignorant of neurology as well? This man is now on death row in Oklahoma.” Grimly O’Donnell jerked the films from the light box and slid them into the envelope.
    “What does this have to do with Warren Hoyt?”
    O’Donnell crossed to her desk, picked up another X-ray envelope and withdrew a new pair of films, which she clipped onto the light box. It was another set of skull films, a frontal and lateral view, but smaller. A child’s skull.
    “This boy fell while climbing a fence,” said O’Donnell. “He landed facedown, hitting his head on pavement. Look here, on this frontal view. You can see a tiny crack, running upward about the level of his left eyebrow. A fracture.”
    “I see it,” said Rizzoli.
    “Look at the patient’s name.”
    Rizzoli focused on the small square at the edge of the film, containing identifying data. What she saw made her go very still.
    “He was ten years old at the time of the injury,” said O’Donnell. “A normal, active boy growing up in a wealthy Houston suburb. At least, that’s what his pediatric records indicate, and what his elementary school reported. A healthy child, above-average intelligence. Played well with others.”
    “Until he grew up and started killing them.”
    “Yes, but
why
did Warren start killing?” O’Donnell pointed to the films. “This injury could be a factor.”
    “Hey, I fell off a jungle gym when I was seven. Whacked my head against one of the bars. I’m not out there slicing people.”
    “Yet you do hunt humans. Just as he does. You are, in fact, a professional hunter.”
    Rage blasted Rizzoli’s face with heat. “How can you compare me to him?”
    “I’m not, Detective. But consider what you’re feeling right now. You’d probably like to slap me, wouldn’t you? So what’s stopping you? What is it that holds you back? Is it morality? Good manners? Or is it just cool logic, informing you that there’ll be consequences? The certainty that you’ll be arrested? All these considerations together keep you from assaulting me. And it’s in your frontal lobes where this mental processing takes place. Thanks to those intact neurons, you’re able to control your destructive impulses.” O’Donnell paused. And added with a knowing look, “Most of the time.”
    Those last words, aimed like a spear, found their mark. It was a tender point of vulnerability. Only a year ago, during the Surgeon investigation, Rizzoli had made a terrible mistake that would forever shame her. In the heat