Alex took a deep breath. ‘So, do you want the official version or mine?’

‘The official version,’ Kim answered.

‘There is no such thing, clinically, as an evil child or a child sociopath. It is felt that a child has not matured sufficiently to be labelled. Specialists will admit to sociopathic behaviour but that’s all. They are more likely to be diagnosed with conduct disorder which can be a precursor to sociopathy.’

‘“Conduct disorder”?’ Kim asked.

‘Starts in early adolescence, more common in boys. Typically selfish, don’t relate well to others, lack guilt, often aggressive. They’ll likely be bullies, cruel to animals, deceitful and rule breakers.’

‘Charming,’ Kim observed.

‘But a child won’t be diagnosed with conduct disorder unless they’ve first been diagnosed with oppositional defiant order which is a precursor for conduct disorder.’

Kim frowned as a vision of Russian dolls sprang into her mind. ‘Hang on, so, you’re saying it’s like an escalation process throughout a child’s formative years. All of these criteria have to be met? Oppositional defiant disorder leads to conduct disorder leads to antisocial personality disorder?’

Alex nodded. ‘And for a child to be diagnosed with antisocial personality disorder they require a conduct disorder diagnosis before the age of fifteen.’

‘Treatment?’ Kim asked, hopefully.

Alex rolled her eyes. ‘There’s no cure or medication, Kim. You know that. Behavioural approaches don’t work as they target specific acts and minimise the bigger picture.

‘The diagnostic criteria ties itself up in knots. A child needs to have experienced three or more of the following in the last twelve months: bullying, fighting, use of a weapon, physical cruelty, mugging, extortion, armed robbery, forced sexual activity—’

‘Jesus,’ Kim interrupted.

‘There are more: fire starting, destruction of property, lying to obtain goods, shoplifting, staying out, running away or playing truant. And one of these must have occurred in the last six months.’

‘Sounds like passing the buck to me,’ Kim observed. ‘Everyone pushing the problem in another direction so they don’t have to make a difficult judgement.’

A slow, lazy smile spread across Alex’s face. ‘Inspector, for once we agree.’

‘Enjoy it, Alex. It’s unlikely to happen again,’ she said. ‘Okay, talk to me about causes.’

Perhaps if she at least understood that she could begin to narrow down the potential suspects.

‘Problems occur more in children of adults who exhibited problems. There may be deficits processing social information or they were rejected by peers as young children; eighty per cent of children outgrow it by adulthood.’

Kim was relieved. She’d been after a number and that seemed like a good one to her. ‘That’s a reasonable—’

‘It’s rubbish,’ Alex said, cutting her off. ‘That’s an impossibly high figure of achievement, which doesn’t take into account a statistic that no one will ever be able to estimate.’

‘Which is?’

‘The ones who have learned to hide it.’

‘Like you?’ Kim asked.

Alex smiled but there was no warmth. ‘Yes, Kim. Exactly like me.’

‘So, what are you saying?’ Kim asked, unsure she wanted to hear this answer. She suspected they were now wandering into Alex’s version of the truth.

‘What I’m saying, Kim, is that chickenpox doesn’t turn into measles once you reach the age of eighteen. The person I am now is the person I’ve always been since I was capable of a conscious thought. I have never loved anything in my life. I have never felt even a second of guilt for any of my actions, only disappointment at what went wrong. I care about no one and nothing. I have no bonds to anyone and every person I meet exists only to give me what I want.’

The intensity of Alex’s expression held Kim in its thrall. She could not look away from the honesty she saw there.

‘Now, what you have to understand is that this didn’t happen on my eighteenth birthday when I could be diagnosed as a sociopath, psychopath or whatever else they call me. I was always this way. Even when I was a cute little toddler learning to walk or a sweet little girl starting at nursery, opening presents in a pretty dress on my fifth birthday. I was always a sociopath except no one had the courage to call it.’

‘Would it have made any difference?’ Kim asked, trying to fight the intrigue she felt.

‘Not to me,’ she said, honestly. ‘I am what I am, and a label wouldn’t have made me act any differently, but it might have persuaded my parents that the last thing I needed was more hugs, love and understanding. These were just more tools for my manipulation toolbox.’

Kim was grateful for the woman’s honesty, despite how uncomfortable it made her. It was a side of Alex she’d never seen.

The woman’s eyes suddenly fixed on a spot above her head.

‘Self-knowledge is a wonderful thing,’ Alex said wearily, as she travelled somewhere Kim couldn’t follow. Alex swallowed deeply. ‘But it doesn’t help when your parents gaze at your sister with uncomplicated adoration and view you with suspicious wariness. Do you have any idea what that does to a child?’ she asked, with a catch in her voice.

Kim shook her head. Her own mother had hated both her and her twin equally. But it was only Mikey in which she had seen the devil.

‘Sweet little Sarah got it all,’ Alex continued, as a tear formed in her reddening eyes.

Kim raised an eyebrow doubtfully, but Alex wasn’t even talking to her any more.

‘I knew as soon as Sarah was born that she was going to be the favourite. I could see it in my parents’ eyes. She was warm and sweet and loving: everything that I wasn’t.’

She wiped away the tear and another formed instantly.

‘From that point on I was excluded from everything. My parents had their perfect little daughter, the one they’d always dreamed of, and the imperfect one, the broken one, was cast off and ignored, classed as weird, strange. Maybe if they’d just tried a little bit…’ her words trailed away as she stared down at the table.

‘Would that have made any difference?’ Kim asked.

Alex raised her head. Her eyes were amused and clear of all emotion. ‘Of course not but look how quickly you were willing to believe it could have done.’ Alex appeared frustrated, as though Kim was a pupil that had not paid attention. ‘With all that you know of me and what I’ve done your own feeble emotions fail you and influence your logical mind. I don’t have that failing. You want to believe that there’s a part of me that can be reached. Even you, as emotionless and remote as you are, have the exploitable weakness of hope.’

Kim shook her head. ‘You are unbelievable.’

Alex smiled as though she’d just been complimented. ‘I learned very young that if I stared at a spot for long enough without blinking my eyes would water.’

Kim felt frustrated at her own willingness to believe there was an ounce of humanity or regret in the woman.

‘The trouble is that you want to believe there is a part of me, however small, that craves normality. I didn’t want family bonds. I didn’t want to be part of a family. You got that and look at the good it did you,’ she said, pointedly. ‘You carry around guilt and hurt that has shaped every decision you’ve—’

‘Alex,’ Kim warned.

Alex pulled a face. ‘Jesus, you really meant it when you said there was nothing in this for me, didn’t you?’

Kim raised an eyebrow.

‘Okay, but do you get it? You’ve got to stop thinking that everyone can be saved. It’s what gives people like me even more power to manipulate you.’

‘So, what should I be looking for?’ Kim asked.

‘A child that is disengaged, withdrawn from relationships with parents, family, peers, teachers. They may be socially isolated by choice. Little attachment and impervious to punishments.’

Kim began to think of the people she’d met over the last few days.

‘But bear in mind, that if they have come to terms with who and what they are, some of these traits might be hidden.’

Kim opened her mouth to respond when her phone vibrated the receipt of a message.

She took out her phone and read it.

She put the phone back and met Alex’s quizzical gaze.

‘Someone special?’ Alex asked.

‘No one you know,’ Kim said, pushing herself backwards from the table. ‘And I now find that I can stomach you no more. You truly are as deplorable as I thought.’

‘But now you understand that it’s not my fault.’

Kim thought for a minute before answering.

‘What you are doesn’t let you off the hook, Alex. You’re here for the things you’ve done. As you just explained to me, all your decisions have been conscious choices. They have been your actions. You understand the difference between right and wrong and still do it anyway. So, it is your fault, Alex,’ she said, walking away.

‘You’re not ready, you know,’ Alex shouted after her.

‘For what?’ Kim asked, turning.

‘Whoever sent you that text message. I saw the smile on your face that you didn’t even feel forming. I don’t know who it was from, but I can tell you now that you’re nowhere near ready.’

‘Fuck off, Alex,’ Kim said, not bothering to explain that the text message had been nothing like that.

It had been a request to meet at the Waggon and Horses for some urgent information.

And the text had come from Joanna Wade.