Ben thought about it. The unhappy, overweight, scar-faced kid who went on to become a loner, preferring the solitude of the wild open spaces. Who had felt impelled to come forward and spill what he’d witnessed to an old school acquaintance, maybe out of some kind of nostalgic spirit. Maybe also because of his own history of childhood physical abuse. The psychology fitted plausibly. But the only way to know for sure was to talk to McGlashan in person.

Grace said, ‘I cross-checked the police records with the DVLA. He drives a blue Subaru Forester, year 2000 model. Current address is a rented trailer home about half a mile outside Kinlochardaich. I reckon we can find him, easy.’ The redness had faded from her cheeks and nose. Her eyes were alive with exhilaration.

‘This is good work, Grace. Excellent work.’

She gave him the crooked smile that he liked so much. ‘Do I get a gold star, or what?’

‘Only if McGlashan does actually turn out to be the right person. Have you told anyone else about this?’

She shook her head. ‘Just you. And nobody else would be wise to the school connection between Jamie and Ewan. So I’d reckon it’s safe to say we’re the only ones who know.’

‘Only, I was wondering how this would sit with your superiors, DI Macleod and DS Coull. This is their investigation. As their subordinate, you can be fired for withholding information from them. And I don’t suppose they take a favourable view of officers conducting their own private inquiries. Why go out on a limb like this?’

She looked at him, and he could see the hardness in her eyes. ‘I love my job. I’m good at it and I don’t take the risk of trashing my career lightly. But my instincts are telling me that something about this whole business isn’t right. If someone’s lying, that’s going to piss me off a great deal. For Ewan’s sake, and for my own, I want to find out what the hell is happening here.’

‘And bring me along for the ride? Why?’

‘Because we share a common purpose. Because two heads are better than one, like they say. And because I don’t feel safe pursuing this on my own. Whoever’s behind all this, they’re obviously prepared to get rough. So before I made any moves I wanted to come and find you. I went to Mrs Gunn’s cottage, but you weren’t there. She told me she’d seen you drive off earlier. From the things you said last night I had a pretty good idea you might be checking out the loch.’

‘All twelve miles of it.’