‘Or they were in a rush. Either way, it was a well-planned job. Efficient. Perhaps CCTV’ll give us a second car.’

Rita crossed her arms. If she’d tutted it couldn’t have been more disparaging.

‘There was no second car,’ she said. ‘Our man drove here in the Toyota.’

‘Man? Or men?’

‘Man.’

‘Care to explain?’

She unfolded her arms as if the effort was considerable and she was doing it just for him. Then she went back towards the trees, speaking over her shoulder.

‘You torch the car, then what? You’ve chosen this spot ’cos it’s near the trees, but also ’cos it’s close to the road.’

They walked through the trees, and there was the wall, just where it had been yesterday. He let her have her Poirot moment.

‘If you wanna be away quick, over the wall you go, and you’re off,’ she said. ‘Which bit would you go over?’

He shrugged. ‘It’s only three feet high. That’s not going to matter, is it?’

‘Take a closer look, partner.’

He resented her cockiness, but he knew there’d be a reason, which made him resent it even more. He looked up and down the length of the wall, just like he’d done yesterday.

‘Rita, if you don’t tell me what I’ve missed this might end up being a double murder.’

She snorted. ‘Don’t worry. I’m not gonna kill you for incompetence! Just look.’

She pointed to a section of the wall about fifteen feet away. The ground in front of it was slightly risen, and there was a protruding stone a little way up, just enough to serve as a step.

‘That’s where I’d go over,’ she said as they moved towards it. ‘Hasn’t rained since Thursday, but it rained Wednesday, right? The rock’s still damp, never really dried out. But see that? It’s still raw.’

He saw it immediately, the lighter hue where a sliver of the old sandstone had been dislodged, right where you’d put your foot.

‘Now,’ she said, ‘if you were carrying something that you had to get over the wall, this stone’d be perfect. You’re desperate to be away. In the rush you drag it over, it scrapes against the stone as it goes…’

Shit. Shit. Even now, as she extended her index finger he could see scratch marks in the dark, weathered stone. Fresh marks. But that wasn’t all. There were the tiniest fragments of something yellow.

‘What’s that?’

‘Scrape marks. And there are minute bits of plastic in them. Something’s been dragged over the wall.’

His mind spun.

‘Could that be from a bike? Y’know, the tape they have on the frame?’