‘Fine. How did it feel when you thought Nick and Anna Foreman were having an affair?’

Harriet cuts in. ‘Don’t answer that, Grace.’

I’d felt hot and bothered when we first came in and I had taken my jacket off, but now I’m chilly, goose pimples on my arms. The milky coffee in the plastic beaker in front of me has gone cold.

‘Were you angry, Grace?’

I don’t answer.

‘Did you use a knife again?’

‘That’s enough,’ Harriet says.

I lean forward, my hands clasped on the table. ‘I didn’t hurt Nick. I loved … love him very much. We were planning to get married. We had just got engaged.’

‘All the more reason to lash out when you discovered his betrayal.’

‘Which I didn’t.’

‘Did you or Nick mention your engagement to anyone? Maybe he called his parents to tell them the good news. Did you tell Lottie?’

I have a sinking feeling. ‘We didn’t have a chance to tell anyone.’

‘So, none of it might have happened. You might have made up the conversation to deflect suspicion about the state of your relationship.’

‘I’m telling you the truth.’

He flicks through his notes, then smiles to himself. ‘If Nick was intending to kill himself at the site of Izzy Wells’ death, the most obvious thing would have been for him to drive himself to Devon. But the car was back in its space on your forecourt the next morning.’

‘His car was there when I went looking for him. It hadn’t moved.’

An officer puts his head round the door and signals to Marsh, who pauses the tape and leaves the room. Harriet and I sit in silence. I wonder what’s happened, what new piece of evidence has come to light. Something that exonerates me, I hope. Why do I feel so guilty about Anna when I haven’t done anything wrong?

Marsh comes back in. He sits down. We wait.

‘You’ll be pleased to hear Anna has regained consciousness,’ he says, his eyes on my face.

I breathe a sigh of relief. ‘Thank goodness.’

‘Are you relieved for yourself, or for her?’

‘For her, of course. But she’ll tell you I had nothing to do with the attack.’

He smiles and switches on the recorder. ‘Let’s go back to the question of why Nick’s car didn’t leave the forecourt on the night he ended up in Devon. We only have your word that it was there all night. None of your neighbours can remember. You could have driven him, dumped his body in the river, hidden the bag and been back by dawn. Then when you subsequently visited the place with Anna Foreman, she pointed out where her sister had left her shoes at the water’s edge, and you realized you’d left the bag in the wrong place.’