Emma, it seemed, had not waited for their approval, but had set off in a determined fashion towards the flapping yellow tape.

‘We’ll wait in the car,’ Magnus called after her.

As Emma raised her hand in acknowledgement of this, Magnus said, ‘We have to talk.’

‘Okay,’ Rhona said, struck by Magnus’s expression.

They turned and headed back on the beaten-down heather path and climbed into the car, this time with Magnus in the passenger seat.

‘What’s wrong?’ Rhona said.

‘Before I begin, I have permission from DS McNab to tell you this.’

‘Okay.’ Rhona waited.

‘DS McNab and DS Clark interviewed a Mr Alec McLaughlin this morning, on my recommendation. I know Mr McLaughlin from Barlinnie where he took part in my research on the take-up of educational classes by prisoners. Just released from prison himself, he contacted me and when we met he told me he had information about the disappearance of Mary McIntyre. DS McNab then arranged an interview with him, which I observed from the neighbouring room.’

‘Go on,’ Rhona said, realizing from Magnus’s expression how significant he felt this interview had been.

‘Before I tell you what he said, I should point out that he took an Open University degree while incarcerated and achieved a first-class honours in Forensic Psychology, so he’s well versed in interview techniques. He was also convicted of raping his partner’s three children, for which he’s been incarcerated for fifteen years.’

‘So whatever he told you could have been a lie,’ Rhona finished for him.

Magnus nodded. ‘However, he was a neighbour of Mary’s whilst a teenager, so knew her and her family well.’ He paused as though they’d reached the crunch of the story. ‘McLaughlin told us that Mary McIntyre was pregnant when she went missing. In fact he said he thought that’s why she disappeared.’

Rhona attempted to assimilate what Magnus had just said. Dr Wang, at post-mortem, had recorded what she believed to be a female of around eleven. The age of course couldn’t be exact, and numerous females as young as ten were recorded as having given birth in various countries around the world, including the United States, although not in the UK.

In many of the listed cases, the one to make them pregnant had been someone close to the child, either a relative or a family friend.

‘What d’you think?’ Magnus said.

‘If you’re asking me if that was discussed at the post-mortem, it wasn’t. Also, like the spleen, intestine and stomach, a pregnant uterus decays early. Plus we’re not yet certain that the victim is Mary McIntyre, and won’t be unless we can extract DNA.’ Rhona explained further, ‘Bogs are acidic and they tend to strip the base pairs off the DNA, so although you can see the DNA, you can’t read it. Think of letters scattered about a page. You can see them but, because they aren’t strung together, there are no words to recognize.’

The rain had come on again with a vengeance, the wind whipping it against the windows.