He shrugged. ‘The police did take it away for a while and then – after they’d completed all the tests they needed to do – they gave it back. I know it sounds weird, but I didn’t know what to do with it once they returned it. I didn’t want to drive it, because it would only …’ He stopped. Bring back bad memories. ‘But I didn’t want to sell it on in case Mum and Dad just walked through the front door one day.’

None of that sounded odd. I’d heard something similar, on repeat, in every missing persons case I’d ever worked. The idea that loved ones might suddenly resurface, out of the blue, even after decades, was powerful and impossible to let go of.

I turned back to the house and saw a garden room with skylights and a grey slate roof at the rear, and then somewhere, out of sight, I heard a weathervane move, its gentle squawk like a bird that had injured itself.

‘What about the neighbours?’ I asked. ‘Everybody got on?’

‘Yeah,’ Ross replied, stepping in alongside me again, his composure restored, ‘they got on well. That’s why Mum and Dad loved it here so much. It wasn’t just the house, it was everything. The eight of them – the four couples – they were always getting together as a group. Dinner parties, nights out, pub lunches. I mean, literally the first year they moved in – when I was in Australia for Christmas – they all got together on Boxing Day.’

I looked to my right, down the remainder of the track, past the third house to where the farm was visible. Each of the properties had driveways and two out of the three had cars parked on them. The Perrys had the Mercedes; the people in the second house had a Porsche Cayenne. There was plenty of money up here, and plenty more at the farm: it might have been less pristine than the houses, but as well as a tractor, and all the farm equipment, there was a new Land Rover Defender parked outside.

‘I just don’t understand what happened to them,’ Ross said.

For a moment, as I looked at him, he was perfectly framed, his parents’ house behind him, the grass too long out front, weeds running rampant, the dark windows giving just a hint of the empty hallways within. He told me over the phone that he’d been trying to keep the house together, the lawn mowed, the rooms tidy, but it was hard when even the process of unlocking the front door hurt. His parents had been gone two and a half years, with no answers and no trace.

But they weren’t the only ones.