Of course, Orkney was rich in archaeological sites, so the first thing they’d had to confirm was that they weren’t digging up the bones of some Viking ancestor, a common enough occurrence and definitely the province of archaeologists.

Rhona found herself quietly wishing that what they were about to unearth might prove to be what Chrissy desired – another bog man or woman – rather than the discovery of a child’s body, like the scene she’d recalled from Saddleworth Moor.

Eventually the hope she’d been nursing began to evaporate. Chrissy knew it too, but said nothing, although Rhona could read it in her eyes as she carefully extracted the last of the peaty soil to expose their first full view of a naked and mummified body.

Possibly a female, she lay on her back, a stuffed plastic bag placed under her head, seemingly to act as a cushion.

They knelt in silence for a moment, the monstrosity of what they had just unearthed overwhelming them.

‘When did supermarkets start giving out plastic bags?’ Chrissy said quietly.

‘Sometime in the sixties, I think.’

‘So we have a time frame at least,’ Chrissy said.

Jen had been right about the effect of the raised bog locus. The exposed body appeared well preserved, the quality of the soil allowing for the mummification of the skin and hair – and, hopefully, the stomach contents.

‘It’s every parent’s nightmare,’ Chrissy said, and Rhona knew she was thinking about her own toddler son, wee Michael.

‘We can raise the tent now,’ Rhona said. ‘Then you can take the soil samples to the van. Get the SCO to give you a hand. Best to give Bill a call too and tell him what we’ve found, while I do a closer examination.’

‘You’re okay to be here alone?’

In the silence that followed Chrissy’s question, the memory of what had happened during the sin-eater case passed between them.

‘I’ll be okay,’ Rhona assured her, although she wasn’t at all certain that she would be.

Well, this is how I find out.

After the tent had been raised, Rhona began to take a series of her own photographs at close quarters, noting the careful laying out of the body and the cushioned head, seemingly at odds with a violent end, although there were marks on the pubic area that suggested stabbing might have played a part.

The long, dark, peat-reddened hair looked carefully arranged on either side of her face, the setting of her arms at a sixty-degree angle to her side resulting in the fingers of the left hand protruding from the dried-out bank.

Something the gravedigger hadn’t anticipated, Rhona thought.

Focused as she had been on the body, she had managed for a while to blot out the strong smell of disturbed earth. Scent, she was acutely aware, lingered longest in the mind and was the most likely sense to trigger a PTSD flashback, and so must be avoided.

Despite her best efforts, the scent now rose to engulf her and with it came the memory of soil raining down on her, to clog her throat and blind her eyes.