Her mum sniffed. ‘Dad found something in your car yesterday. He went out to check the tyre pressure and oil. You know how he’s a stickler for that kind of thing. And he found – he found your hammer.’

Andrea nodded. ‘So?’

‘Why do you have a hammer in your car, darling?’

‘In case someone attacks me. Carjacking.’

Her mum gave a sad, soft smile. ‘You don’t need to lie any more,’ she said. ‘I know what you are.’

Andrea stared at her.

‘What do you mean?’

‘Ever since you were a baby, I knew something was wrong. You weren’t like the other babies, from the very start. It was obvious. You didn’t react like them. You didn’t smile at me, you didn’t show any emotion. At playgroups you weren’t interested in the other kids at all. You only sat, and watched. I asked the doctors and they shrugged it off as something developmental, but I knew. A mother always knows.’

‘This is crazy,’ Andrea said. ‘You sound like a madwoman.’

‘No, I don’t. As you got older it continued. I did some research; I knew what was happening. You didn’t care about anyone else. It was obvious. Eventually you learned to smile at the right times and say the right things, but it was an act. It’s why we gave you that dog. We wanted you to form a connection with something outside yourself.’

‘I liked Allie,’ Andrea said.

‘You killed Allie,’ her mum replied. ‘You poisoned her.’ She held up her hand. ‘But that’s all in the past. I hoped you’d find a way to live. I hoped it wouldn’t come to this, but I always knew it was a possibility. I wondered if it was you killing those poor people – they were always killed on nights you were working – but there was no proof. I didn’t want to believe it. But then Dad found the hammer.’ She smiled the same sad smile. ‘So I know, Andrea.’

There was no point denying it.

‘So what’s next?’ Andrea asked.

‘We can get through this,’ her mum said.

‘Are you going to tell the police?

Her mum shook her head. ‘We should. But you’re our daughter. And what good would it do? We can help you. We have a plan, and we won’t let you kill again, so there’s no point involving the police. It makes no difference.’ She looked Andrea in the eyes. ‘Unless you tell me you don’t want our help?’

‘Of course I do.’

‘Dad and I want to talk it through with you at the house, but before that I need to know you’re committed to fixing this, Andrea.’

There was only one answer she could give.

‘I am, Mum. I promise.’