Burton sits back in his seat and picks up his mug of what must now be cold tea. He takes a sip but doesn’t seem to mind. ‘So, seat belts, when they lock at speed, the mechanism gets super-hot, super-quickly. There are a lot of forces involved in an accident like this one – people thrown forward in their seats, a lot of pressure on the seat belt. And it deforms. See, like this one.’

He clicks around again and points at the screen. Freya can clearly see raised ridges and bumps on the black fabric.

‘And the position of these bumps would indicate someone else was in that car.’

‘But – what?’ Freya asks. ‘Is it possible to survive a crash like that? They must have been injured?’

‘Absolutely,’ Burton agrees. ‘People in car accidents get thrown around like they’re in a washing machine. Head injuries on the A pillar, leg injuries as the engine and dashboard push forward into the car. Whiplash, at least.’

‘So where did they go?’

Burton shrugs. ‘We had no other evidence to show anyone was there. But—’ he adds, remembering some other information. ‘The airbags definitely deployed, so whoever it was would have been blinded.’

Freya knows that when airbags explode out of the dashboard a fine white powder comes with them. It’s designed to stop them catching fire, but has the added effect of temporarily blinding whoever’s sitting there. It’s not fun.

‘Did you get anything from the engine control module?’

‘Burnt out. Not even the engineers in Amsterdam could save it.’

‘And there were no other witnesses?’

‘Nope. We put appeal boards up at the scene, did a media release, but nobody came forward.’

Freya sits back in her chair, her pen lowered. ‘So what did you conclude?’

Burton shakes his head. ‘The only thing we could – accidental death from a road traffic accident. My guess? The guy was drunk, as the papers said.’

‘Why do you say that?’

‘The JD bottle in the footwell. You know about that, yeah?’ Freya nods. ‘And the fact that he comes flying off a totally straight road. Look at it.’ He pulls the photo back on the screen. ‘Not even a bump in the tarmac. The patterns on the road and the tyres are different depending on whether the car was under power when it crashed—’

He flicks through another few photos – black marks on the road, the remaining tread on the tyre. Burton continues, ‘—and this one never slowed. He’s pissed, dozes off a bit, comes to, realises he’s strayed into the middle of the road and overcompensates, losing control and charging into the tree.’

Freya nods, thinking it all through.