‘What exactly did Aidan say?’

I close my eyes. ‘He said, “Years ago, I killed someone. I killed a woman. Her name was Mary Trelease.” ’

‘ “Her name was Mary Trelease”?’ Sergeant Zailer looks puzzled. ‘So he said it as if she was someone you’d never heard of, then? He didn’t know you knew her?’

I should have anticipated this question. My mind starts to churn. ‘I don’t know her.’

‘What?’

‘I don’t know Mary Trelease.’

‘Then . . . Again, Ruth, you’ll have to forgive me if I’m being slow here, but if you don’t know her, how did you know she was still alive when Aidan first said he’d killed her?’

She wouldn’t believe me if I told her. Still, I’d risk it if I thought I could say the words without bringing my first meeting with Mary to life again, as if it was happening now. Even thinking about telling the story makes me feel hot and panicky. I stare into my half-drunk tea, squirming, wishing she’d ask another question, but she doesn’t. She waits. When I can no longer bear the silence, I say, ‘Look, all you need to do is check that she’s alive. She lives at number 15 Megson Crescent . . .’

‘On the Winstanley estate?’

‘Yes, I . . . I think so.’ I can’t appear too certain, having claimed not to know her.

‘Megson Crescent is a contender for the title of roughest street in Spilling. Most of the ground-floor windows are boarded up.’ Sergeant Zailer raises an eyebrow. ‘Ms Trelease is a struggling artist, I take it? She can’t be making much money from her painting if that’s where she lives.’

I feel a hysterical laugh rising inside me. ‘She makes no money from it.’

‘Does she have a day job?’

‘I don’t know.’

‘Don’t you?’ Charlie Zailer says smoothly, as if passing comment on the weather. ‘Do you think I don’t know when I’m being lied to, Ruth? Do you think I don’t meet liars every day? I do—liars of the highest grade. Shall I tell you about some of them?’

‘I’m not a liar. I don’t know Mary, and I hadn’t heard of her when Aidan told me . . . when he told me . . .’

‘When he told you that he’d killed her, years ago.’

‘That’s right.’ My words sound like someone else’s, as if they’re not coming from inside me but from somewhere far away.

‘You’re panicking, Ruth, and you’re spewing up lies faster than the magic porridge pot spewed up porridge. Remember that story from when you were a kid?’ Sergeant Zailer yawns, leans back in her chair. ‘Is it possible Aidan killed another woman with the same name?’ she says, as casually as if she were suggesting the answer to a crossword clue. ‘I know Trelease isn’t a common surname, but . . .’

‘No,’ I say, my voice cracking. ‘I could see the details were familiar to him when I told him. That she lives on Megson Crescent, that she’s an artist, forty-ish, with long black curly hair, silver streaks in it where she’s starting to go grey.’ His face: the absolute recognition, the fear, in his eyes. ‘It’s the same woman, the one he’s sure he killed. I’m not making this up! Why would I?’