‘But this suspect took three shots.’

‘To me, that doesn’t sound like a real professional.’ ‘There was no sign of any casings in the field, so we presume our suspect stayed long enough to pick them up.’

‘Well …’ began Cooper.

‘Yes?’

‘At night, in a ploughed field, that would be quite tricky. You’d be lucky to find one, let alone all three.’

‘True,’ agreed Hitchens, looking at him with interest.

Cooper leaned back for a moment and pictured the scene. He imagined himself sitting at the wheel of a car at night, in a ploughed field, with the driver’s window open and three bullet casings lying on the ground somewhere outside the vehicle.

‘Not just tricky,’ he said. ‘It would mean the suspect getting out of the car and leaving his footprints in the soil. He would pick up earth on his shoes and trail it back into the vehicle. That’s three possibilities for trace evidence. But the scenario doesn’t fit, does it? It’s not consistent with the planning before and after the hit.’

‘And there were no footprints in the area where the shots were fired from, just tyre marks,’ pointed out Hitchens. ‘Maybe the casings fell close enough to the car that the gunman was able to lean out of the door and pick them up without leaving the vehicle.’

‘No, that won’t work. It was a high-powered rifle. The casings would have been ejected at speed.’

‘What, then?’

‘The only possibility I can see is that the casings must have been ejected inside the car.’

‘Is that possible? If he was firing a rifle from the driver’s seat?’

‘The car was facing northwards, up the field, wasn’t it? With the back fence of Bain House on the driver’s side?’

‘Yes.’

‘Then, no,’ said Cooper. ‘I don’t think it is possible. Whoever fired the rifle would have had to be in the passenger seat.’

There was a sudden buzz of interest. Cooper felt himself flushing – not with embarrassment, but excitement. He was sure he’d got this right. He could see it so clearly.

‘We’ll have to get this checked out properly,’ said Hitchens.

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?’

‘A webcam. You can go on the internet and see a view of Matlock Bath promenade. I think they have it running pretty much every day.’

‘Who operates this thing, Cooper?’ asked Kessen, leaning forward in his chair.

‘I think it’s a photographic museum.’

‘Time lapse, I suppose?’

‘Yes, sir. But no worse than most CCTV systems.’

‘It would be too good to be true if it caught Rose Shepherd. But let’s check it out anyway.’

Hitchens waited to see if the DCI had finished. ‘Next thing,’ he said. ‘We’ve had the victim’s phone records checked, and we now know that a call was made to Miss Shepherd’s home number at three o’clock on Sunday morning. The call lasted only twelve seconds. As you might have guessed, the caller used an unregistered pay-as-you-go mobile. No account, no address. If our suspects knew what they were doing, they’d have bought a phone specifically for this one call, then dumped it. And it looks as though they knew exactly what they were doing.’

‘Pay-as-you-go phones,’ said someone gloomily. ‘The biggest gift that was ever made to drug dealers.’

‘And paedophiles. And terrorists. We need some legislation on this one, don’t you think, sir?’

‘That’s way above our heads, I’m afraid.’

‘Right. We’re just the poor buggers who have to pick up the pieces.’

Hitchens sighed, and departed from his notes. ‘Actually, true anonymity is hard to achieve these days. We might not be able to identify the purchaser of a prepaid mobile, but if the call credits are paid for by card or cheque, the payments can be traced back. Also, we can track the phone’s physical location, provided it’s switched on. But, in this case, assuming our suspects do still have the phone, it’s been switched off since the call to Miss Shepherd.’

‘Dumped it, like you said, sir.’

‘Exactly. Now for the victim’s background. You’re probably aware that this is proving a real headache. Whatever her reasons, Rose Shepherd went to extraordinary lengths to protect her privacy. She left almost nothing of a personal nature to give us an angle on her life. However, we’ve had time since yesterday to go through her cheque books and bank statements.’

‘Anything interesting?’

‘To be honest, I’ve never seen such a boring credit card statement as hers. I was hoping for something a bit revealing – I don’t know, a purchase of expensive wine, or a subscription to a porn website. But nothing out of the ordinary. Not a thing. Her bank statements show her Council Tax, electricity bill and water rates going out on direct debit. Her BT phone bill was paid online by credit card. There’s nothing here that tells us anything about her. All the evidence we have points to Miss Shepherd being a model citizen, paying her bills on time, being no trouble to anyone.’

‘Much too perfect to be true.’

‘Absolutely. I think we can all agree on that.’

‘Perfect citizens vote, don’t they? Is she on the electoral register?’

‘No. And she’s not in the phone directory either,’ said Hitchens. ‘All we’ve got is her passport, plus her bank statements and utility bills. The other strange thing is that there are no obvious personal contacts. There is an odd entry on a blank page in her address book, though. It’s just three digits: 359.’