‘Of course,’ said Fry, waving a hand impatiently. ‘But, in this instance, the identity of the victims is crucial. We not only have to find out who they were, but how they were connected to each other – and we need to do both of those things before we can even begin to focus on any suspects. How did these women come to be at Pity Wood Farm? If we can start to build up a picture of them, Ben, we’re halfway there. Damn it, if we can do that, we’re almost all the way there.’

Cooper looked thoughtful. It was the one thing Fry could say about him – he always listened and considered what she said, even if he then went off and did something entirely different.

‘In a way, it feels as though there ought to be a third victim,’ he said.

‘What?’

‘A third victim. One who came in between these two, perhaps. I don’t know. But a victim that would fill in the gaps and make the connection. The ones we’ve found might not be Victims A and B at all, but A and C. It could be the absence of the real Victim B that’s making them look as though they’re not part of a sequence.’

‘Explain yourself, Ben.’

Cooper got up and began to pace in frustration, as if he was struggling to articulate in plain words some nagging but elusive idea that had been slithering at the back of his mind.

‘What I mean is, there might have been a third person who had connections to these other two. If there was a middle victim, the pieces could fall together. At the moment, it’s like there’s a black hole, a missing section where all the links have been broken.’

‘But there isn’t a third victim.’

‘Not that we’ve found, Diane.’

Fry thought of the excavated farmyard. ‘Well, not at Pity Wood. There isn’t a third victim there. We’d have found her by now, Ben.’

‘Has anyone checked that old caravan?’

‘The search team gave it an initial sweep. The SOCOs haven’t got round to it yet, but there’s certainly no body in it, if that’s what you’re thinking. Not even any personal possessions that might lead to an ID.’

‘No, but there might be some trace evidence,’ said Cooper. ‘It was almost certainly being used to house itinerant workers.’

‘I’ll suggest making it a higher priority. OK?’

But Cooper continued to pace, unsatisfied. ‘These victims didn’t go missing at the same time,’ he said. ‘There’d have been a major enquiry, if there had been three. We’d still be looking for them now. There must be a connection between them, though.’

‘I repeat, we haven’t found three bodies. It sounds ridiculous to say “only” two, but …’