‘It’s always the dog walkers,’ Burton says, with a smile. ‘Remote crime scene, guarantee it’ll be those guys that find them.’ He wiggles his mouse to wake up his computer, then clicks around, finding the right file.

A photograph is loaded and Freya cranes forward. A long, straight road, early dawn, trees on one side, tall hedge on the other. To the left, a car waits, half on, half off the road. Even from this view, taken from behind, Freya can see the effects of the fire.

‘The guy saw the flames, called the fire brigade. They were the first on the scene. They called us.’

‘No ambulance?’ Freya sips her tea again and listens to the sergeant talk.

‘No need.’ Burton clicks the photograph forward and a different view appears on the screen. A side view, glass smashed, black body in the driver’s seat. ‘They knew he was dead. Melted onto the seat. Took the body recovery team an age to get him out.’

‘And you did the investigation?’

‘Yeah. Let me get the report up.’

More clicking and a document loads. Burton scrolls down through the text.

‘So,’ he begins. ‘Debris field was wide, shit scattered all across the road.’ A new photo, small reflective studs and yellow paint visible on the grey concrete next to the familiar yellow triangles marking the positions of the evidence. ‘You can see from the markers the car swerved, seemingly out of nowhere, skid marks here—’ a large finger prods the screen ‘—and here. But he must have been going at some speed. There was a huge amount of damage to the vehicle.’

Another photo, the bonnet of the car concertinaed around the trunk of the tree.

‘And why did it catch fire?’ Freya asks, finishing her tea and putting the mug back down, freeing up her hands to take notes.

‘Mechanics had a look at it back at the compound. The force of the crash sheared the bonnet completely from the car, which dislodged the fuel injectors from the engine. Petrol sprayed on a hot engine, and boom.’

‘So, unlucky?’

‘Very. Especially for us. Fire destroys absolutely everything. Both airbags deployed, and we’d normally check them for mouth DNA, work out who’d been sat where, but there was nothing left.’

‘Sorry.’ Freya stops him. ‘What do you mean, “who had been sat where”? Trevor Stevens was the only one in the car, wasn’t he?’

‘Well, yeah. That’s what we concluded in the end. But, you know, I always wondered. See here—’ Burton goes back to an earlier photo. ‘The passenger door was found open. Of course,’ he adds, seeing Freya about to speak. ‘That could have happened in the crash, but the seat belt was odd, too.’

‘What do you mean?’