‘So how did the police find Grace?’ I say. ‘Why did they come for her?’

‘Apparently she woke up in the woods sometime around dawn,’ says Isobel. ‘By that time we were long gone but her father’s blood was splattered on her clothes. It must have got on to her when he fell. According to the police she told them she’d staggered back to the house after that and holed herself up in this room.’

I look around at the stark white walls and shiver, imagining Grace as a young teenager in here all alone, scared and confused.

‘Someone must have noticed she was here alone because the police were given an anonymous tip-off and found her here covered in blood,’ says Isobel, her face hardening.

‘Anonymous?’ I say, frowning. ‘But I thought Grace and her father had kept themselves to themselves. Who would have –?’

I stop then, noticing the strange expression on Isobel’s face.

‘You called them?’ I say, my voice shaking with rage. ‘You framed Grace for the killing? I don’t believe it. How could you, Isobel? You were supposed to be her friend!’

‘Friend?’ cries Isobel. ‘She was never my friend. She was just some misfit who’d attached herself to me. We were never friends.’

‘She was sent away,’ I say, trying to keep calm as I remember Grace and her small acts of kindness that got me through those dark days. ‘She’s in prison now.’

‘She’s not in prison for what happened to her father,’ snaps Isobel. ‘She was sent to a young offenders’ place for that and got all sorts of therapy. What you don’t realize is that Grace is mad. She always was. When the police turned up that day she told them she’d killed her father. She was a lunatic.’

‘She told them because she was covered in blood and had no recollection of what had happened,’ I say. ‘She was scared and confused.’

‘She was dangerous,’ says Isobel, her eyes blazing. ‘You forget she’d been brought up by that madman, utterly untamed. After she was released from the young offenders’ place she got slung back in prison for all sorts of things: theft, assault, GBH.’

‘How do you know all this?’ I say.

‘I kept myself updated,’ says Isobel sourly. ‘Googled her name from time to time, that sort of thing. It was in my interest to know what she was up to.’

‘But everything that happened to her stemmed from that night,’ I cry. ‘For being framed for something she didn’t do. Grace was a good person. I know that because I spent time in prison with her. I saw her kindness first-hand. Isobel, you have to tell the police what happened. You must.’

‘Don’t tell me what I must do,’ she yells, jumping to her feet. ‘I know all about you and what you did to your husband. I saw him on the news the other night, poor chap, begging for his little son to be brought back. What kind of a wife and mother does that?’