But Cooper mimed holding and pointing a rifle. ‘Imagine it. With the window wound down, you’d want to rest the barrel of your weapon on the door for stability while you were aiming. It wasn’t too distant a shot – a hundred yards is nothing. But even so, you’d want to be sure. That means the stock and the chamber would be well inside the vehicle, so your casings would eject against the back of the seat.’

‘He was shooting from the passenger seat?’

‘No, it would have to be from the back seat,’ said Cooper.

‘Wait a minute. This would suggest two suspects, right?’

‘One to drive and one to shoot. It’s the only way.’

‘Two suspects . . . It makes sense,’ said DCI Kessen, speaking for the first time. ‘They went into the field, did the job and drove straight out again. No one would want to hang around climbing over seats or packing a weapon away. From their point of view, they were already taking a bigger risk than they might have cared for. Having a separate driver would cut down tremendously on the time they were exposed. Unfortunately, our witnesses say there was only one person in the Astra.’

‘OK. That was useful, Ben. Thanks.’ Hitchens looked at his file, indicating that he wanted to move on. A discussion could last all morning if they got stuck on one subject.

Cooper glanced across at Fry, who was watching him closely. She nodded and almost smiled. That was high praise indeed, coming from her.

‘The good news is that we’ve got some calls coming in from the public in response to photos of Rose Shepherd in the media this morning,’ said Hitchens. ‘So her passport photograph wasn’t too out of date. Most interestingly, we’ve got a couple of potential sightings in Matlock Bath on Saturday afternoon. That would be between six and sixteen hours before she was killed – in fact, around twelve hours, if we put any reliance in the evidence of her neighbours.’

The DI brought up a map of the area for everyone to see. ‘Matlock Bath is no more than three miles from Foxlow – on the A6, just south of Matlock itself. It’s a popular tourist spot, even at this time of year, so it would have been busy on Saturday afternoon. Maybe that’s why she chose it – anonymity in crowds. But if these are positive sightings, it didn’t work out that way. She must have stood out somehow for members of the public to remember her.’

‘There’s no CCTV in Matlock Bath, is there?’

‘No. This isn’t Glossop we’re talking about. They don’t expect major crime on the street. There will be some limited CCTV systems on commercial premises, but nothing on the street.’

‘There’s a webcam,’ said Cooper.

‘A what?’