He has the good grace to look regretful. ‘I know you’ve been asked this before, when you were first interviewed after Heather was taken into hospital, but have you thought more about the victims, Deirdre and Clive Wilson? Are you sure you don’t know them?’

‘No. I’ve never heard of them. Neither has Adam – Heather’s husband. We can’t think of any link between Heather and those people.’

‘Have they ever stayed at the caravan park?’

‘Not that I know of, but I haven’t checked the register. And I don’t recognize them from the photos that have been in the paper. We’ve not been very busy, really, since about October. It’s too cold for camping.’

He reaches inside his coat and takes out a little notepad. He flicks through it and Margot’s unease intensifies. Eventually he says, ‘Your husband, Keith Powell.’

‘Yes.’

He consults his notes. ‘He was killed on the twenty-first of April 1990 on the farm you used to own in Kent. Is that correct?’

Margot suddenly understands why Ruthgow has come all this way. ‘That’s right.’ Her mouth is so dry she has to get up to pour herself a glass of water. They’d once bonded over the death of their spouses. He hadn’t known then, of course, exactly how Keith had died. It was a secret she’d hoped she would take to the grave.

Ruthgow waits until she’s returned to her seat before continuing. ‘He was killed with a shotgun. Similar model used by Heather to shoot Deirdre and Clive Wilson.’

Margot blinks back tears. ‘It was an unfortunate accident, that’s all. No charges were brought.’

Ruthgow doesn’t say anything, he just surveys her with those calm, unreadable eyes, and she realizes it’s not just his appearance that has changed in the intervening years: back then he was more emotional, warmer. She’d felt she could tell him anything after Flora had gone missing. He was on her side, more than any other officer working on the case at the time. She’d sensed some of them saw Flora Powell as a typical teenage girl who’d lied and kept secrets from her family, including a boyfriend. Not Gary Ruthgow.

And now here he is with his thinly veiled accusations.

‘I’m sorry, Margot, I really am, but this doesn’t look good. A dead father, a missing sister. And now two more dead.’

Margot stands up, pushing her chair back. She knows exactly what he’s insinuating. Hasn’t she thought the same thing herself in her darker moments? ‘I want you to leave. Please, just go!’