Frankie held back her breakfast which repeatedly threatened to make a reappearance and raised the office SLR – taking shot after shot of Oscar’s corpse, zooming to focus in on his neck. She spotted the rabbit dangling beside him, strangely companion-like in death and added a few shots of that unlikely pairing. The wires disappeared into the leafy canopy above, but she took a few photos anyway.

Corstorphine turned away from the macabre sight. He’d seen dead bodies before, it came with the job – but not like this. Oscar’s body hung there like a medieval sacrifice, the gaping second mouth screaming silent obscenities at his back. He allowed himself time to process the image as he walked back towards the quad bike they had just passed, down the track, spotting snares spilled on the ground as the bike had toppled into the burn. He retrieved the rifle from its side holster, sniffing the barrel to confirm it hadn’t had recent use and took the keys out of the ignition. On second thoughts, he carefully fetched the engine oil tin, examining it suspiciously with a fair idea of what it contained. Looking back towards the tree, fresh tracks indicated where the quad had left the path, no other tracks were obvious. The rifle and tin were placed in the back of the Land Rover, wrapped in a plastic sheet.

“Sir!” Frankie’s voice carried a note of query. “What do you make of this?”

He followed the line of her arm to a white stick lying beside the track, immediately under the tree. It was a bone harpoon, more like the kind of thing he’d expect to see used by an Inuit fisherman than lying incongruously in some Highland glen.

“Could be one of Oscar’s tools of the trade.” His response was neutral, unsure of the purpose of such a tool. “Wouldn’t put it past him to have something like that for getting at rabbits in burrows, perhaps setting snares from a distance.” He stooped to pick it up in a gloved hand, then noticed a gear wheel, partially obscured by the heather overhanging the path. “Now that’s interesting!” Frankie paused from photographing the harpoon to look at the object he held up into the sunlight. It was a gearwheel, each tooth perfectly identical to the next as they wrapped a geometric pattern around the rim of a circular bone disk. He turned it, admiring the skill with which it had been manufactured. “Was Oscar much of a creative artist?”

“Not to my knowledge, sir. He’s...” She paused, rearranging her words to account for the past tense. “He was creative with his fists but more well known as a piss artist.”

Corstorphine nodded thoughtfully, placing the gearwheel into a plastic bag. He peered up into the tree, wondering whether he was still capable of emulating childhood feats of tree-climbing heroics to look more closely at the wire support. “See if there’s anything else unusual around here.”

They both undertook a fingertip search of the track, picking up tiny fragments of carved bone and wood and placing them into evidence bags as they went, with Frankie painstakingly photographing each item and location.