‘Good,’ Baker says, and Freya doesn’t like to argue with the finality in his voice. ‘Get your report to me by end of day tomorrow and get back to the Miller case. Between you and me, Butler’s coming up a blank. I need someone else to help him finish his enquiries and put it to bed. Will that be a problem, West?’

‘No, guv,’ Freya agrees, and hangs up the phone.

She sits back on her sofa, the phone still in her hand, evidence twitching in her head. So Trevor Stevens was looking for salvation. Seeking to make amends. He reaches out to the husband, Liam Riley, has a nice chat. Not so much with Butler, but then that’s not surprising. Freya doesn’t take her boss for the forgive and forget sort. Stevens is going to AA meetings, speaking to his sponsor. There’s no evidence he was drinking, bar the burnt JD bottle in the footwell, that Freya knows he didn’t buy at the petrol station.

So where did it come from? Freya frowns. She could try and find out: track down every single place he shopped in the days before his death? It’s possible, she thinks. She could pull his financials, contact every shop, assuming he paid by card. But it was two years ago, a tired voice says in her head. And what if he paid in cash? There’d be no trace.

And even if he had bought it, what then? It would wrap things up nicely, but wreck the wife’s image of her dead husband. There are so many lives ruined already, why make it worse?

Freya gets up, goes to the fridge and cobbles together some lunch from the last pieces of cheese and bread. As she eats it, she sits in front of her laptop, running the CCTV footage again. The same couple, the man and the woman. The same faceless man, the same conversation. And no way of knowing who any of them are.

She gets up and makes herself a cup of tea. But when she sits back down, she realises the disc has still been running. Churning out the next file, black and white again, unrecognisable customers on the screen. And that’s when she realises – it’s a different camera. She didn’t see the other one. It must have been hidden in the corner of the shop, quietly recording footage from the door.

Barely daring to think, she scrolls through the timestamp, the clock ticking round at the bottom of the screen. Daylight outside fades; the lights switch on in the petrol station.

More customers come in through the door, then go out of shot. They walk up the aisle, buy chocolate and sweets. Pay, chat, smile.