‘Camera’s mounted too high,’ Gillard said.

‘If it was a bit lower we could see his face,’ Hoskins said, pausing the replay.

‘Doubt it. Too much condensation on the screen.’ As it was, there was only the sleeve of a dark car coat, with a single narrow hi-vis stripe on it visible through the side window.

‘He’s wearing gloves,’ Hoskins said. ‘You can see a hand on the steering wheel. But watch this.’ He hit play again.

As the vehicle swung backwards and right off the drive and onto the road, a bathrobed figure sprinted into view from immediately underneath the camera. The man, who looked to be in his late thirties and athletically built, showed quite a turn of speed for someone in slippers, intercepting the car just as it ceased to move backwards. He grabbed the passenger-side door handle, leaned back and tugged, but when it accelerated forward, the change of direction seemed to catch him off-balance. He was jerked off his feet and fell sideways, still holding on to the door. His dressing gown flapped open, hairy chest and parts south briefly visible as he rolled on the road.

‘Ouch, that’s going to hurt,’ Gillard said.

‘Yep, dragged up the road on his bare bollocks. Now watch the slipper,’ Hoskins said.

The black item flew off the victim’s foot as he was knocked sideways, shooting straight up and out of view before landing on the left of the picture, enough to again trigger the motion sensor as the vehicle sped out of picture to the left. It was in that final sharply illuminated frame or two that there was just a glimpse into the speeding vehicle.

‘He’s wearing a balaclava,’ Gillard said. ‘But there’s a few pixels of face. He’s white. See if you can get it enhanced.’

Hoskins nodded. ‘Consider it done, boss. We’ve got only one ANPR hit on the vehicle, on the approach to the M4. Take a look to see if we’ve got any roadside cameras nearby.’

‘Good work,’ Gillard said checking his watch. ‘How is the victim?’

‘He got gravel rash on his bits, sprained ankle and some wrist tendon strain,’ Hoskins said. ‘But that was a week ago. He’ll live. I’m going to see him today.’

The detective chief inspector suddenly lost interest in the comedy. An email from the lab had pinged into his inbox.

‘Shit,’ he said.

Hoskins looked up at him.

‘The DNA test showed the dark hair I found in the Allegro belongs to Beatrice Ulbricht.’

Hoskins stretched his face in sympathy.

‘Shit! Her mum and dad are upstairs,’ Gillard said. He’d really hoped, against the odds, that the disappearance of this talented young woman would end happily, but that now seemed even less likely. What on earth was her hair doing in some ancient car that had been washed off a caravan site? It just didn’t make sense.

He tapped on Alison Rigby’s door, hearing the genteel clink of coffee cups within and a background hubbub of conversation. Called in, he was immediately tracked by the expectant faces of Karl-Otto and Lisbeth Ulbricht. The chief constable explained to him that she had already briefed them on the current state of the investigation. ‘I was wondering if there was anything new since the start of the day?’