Free Over the Edge by Jonathan Kellerman

the report, Chancellor's body had been trussed up, Ford's was prostrate, and Jamey was sitting cross-legged on the floor between the two corpses, clutching a long-bladed knife and a swatch of lavender silk. He seemed in a trance, muttering incoherently - something about bursting arteries and zombies - but went wild at the sight of the officers. It took several policemen to subdue him, and he was put in restraints before being taken away.'
    I remembered the boy's phone call, the terrible images.
    Souza kept reciting:
    'They booked him in the county jail, placed him in isolation, and phoned me. I set out immediately to do all the lawyerly things at my disposal in order to obstruct the investigation: filed a writ prohibiting interrogation because of mental incompetence, protested at the lack of adequate medical care at the jail, and demanded release on bail or immediate transfer to a psychiatric facility. The writ was complied with - a minor victory because he's too incoherent to be interrogated anyway. The medical care issue was handled by allowing Dr. Mainwaring to visit him and administer medication under supervision. In view of the boy's escape and the enormity of the charges, you can imagine how the bail transfer request was received. He remains at the jail, curled in his cell like a foetus, mute and unresponsive.'
    The attorney sat back in his chair, picked up a fountain pen, and suspended it between his index fingers. As promised, he'd laid out the facts with the precision of a draughtsman. The end result was the blueprint of a nightmare. I searched Dwight Cadmus's face for reaction, found only arctic immobility.
    Souza got up from behind the desk and straightened one of the cups in the tea set. Instead of returning to his chair, he stood with his back to the French doors, outlined squarely against the glass.
    'I've done some research into your background, Doctor. Your scholarly credentials are impeccable, you have a reputation for honesty, and you've had an impressive amount of courtroom experience as an expert witness -though I don't believe any of it was in a criminal trial.'
    'That's right,' I said. 'I testified at the Casa de los Ninos trials as a material witness. My expert testimony's been limited to child custody issues and personal injury cases.'
    'I see.' He thought for a moment. 'If it sounds as if I'm quizzing you, forgive me. How familiar are you with the notion of insanity?'
    'I know it's a legal concept, not a medical or psychological one.'
    'Exactly,' he said, obviously pleased. 'A defendant may be a stark, raving lunatic and still be judged legally sane. The essential question is the capacity to distinguish right from wrong. Diminished capacity dictates the absence of guilt. I want your help in constructing a dim cap defence for Jamey.'
    'I thought the legislature eliminated psychiatric testimony in dim cap cases.'
    He smiled tolerantly.
    'The Twinkie defence hubbub? Not at all. Psychiatrists and psychologists are no longer allowed to get up on the stand and draw conclusions about diminished capacity, but they're permitted to present clinical data from which those conclusions can be drawn. For the purpose of this case the distinction is insignificant.'
    'Despite that,' I said, 'I have lots of problems with the concept of diminished capacity.'
    'Really? What bothers you about it, Doctor?'
    'For one, it asks us to go beyond our training and pull off the impossible - crawling into someone's head and reconstructing the past. It's little more than officially sanctioned guesswork, and laymen are starting to see through it. On top of that, it lets too many bad guys off the hook.'
    Souza nodded, unperturbed.
    'That's all very fine, in theory. But tell me, when you spoke to Jamey on the phone, how did he sound?'
    'Agitated, confused, hallucinating.'
    'Psychotic?'
    'I can't diagnose from a phone call, but most probably.'
    'I appreciate your professional caution, but believe me, he's psychotic. Severe paranoid