Murfin was standing by the window of the tattoo parlour, just behind the artisan bakery, partially obscuring a poster advertising ear-lobe tattoos.

'Becky?'

'Right behind the stall.'

'Excellent. Let's hope the uniforms stay out of sight until we've got the cuffs on.'

Without showing any signs of hurry or drawing attention to themselves, they closed in towards Gullick's stall. A young a.s.sistant was weighing out onions for a customer, and Gullick himself moved down to the end of the stall to shift some empty boxes. When Cooper was within a few yards, the customer paid for her onions and the stall was clear.

'Right, move in.'

Cooper picked up speed as he moved towards the stall. But Gullick, seeming to sense that something was wrong, looked up and spotted him. Cooper saw the flash of recognition in his eyes. A pile of boxes went flying as Gullick barged his a.s.sistant out of the way and ran round the end of the stall, toppling a pile of Golden Delicious, which spilled into the aisle and rolled under the feet of pa.s.sing shoppers.

'He's spotted us, Ben,' said Hurst. 'He's doing a runner.'

Cooper could see Hurst grabbing for Gullick, but missing.

'Police!' he called. 'Stay where you are!'

'd.a.m.n, I almost had him there,' called Hurst.

'Police! Stop!'

Gullick took no notice. It never did work anyway, unless you had a dog handler to enforce the command.

Cooper tried to dodge between the shoppers, who milled about in confusion, getting in his way. There was a crash, a splintering of wood, and someone screamed as if they'd fallen on to the stone paving.

'Gavin?' said Cooper.

'Yeah?'

'Where the h.e.l.l are you?'

'Right here. Just waiting for you to join me, like.'

'What?'

Cooper pushed his way through the crowd, and Becky Hurst came panting up behind him. When the press of bodies cleared, he saw Gavin Murfin in his old anorak, standing there like someone's mildly confused uncle out doing his weekly shop.

At Murfin's feet lay a large shape in jeans and a white T-shirt, squirming desperately in his efforts to free himself from a heap of Union Jack rugs. Murfin bent, snapped on the handcuffs in two quick movements and straightened up again.

'You youngsters,' he said. 'All that running about, and it doesn't achieve a thing.'

Today was also Emergency Services Day in Edendale. Cooper had forgotten that. The whole of Victoria Park had been taken over to mount displays for the public. Crowds of civilians were pa.s.sing through in their hundreds.

This park was also the site of the annual Christmas market. It was a popular attraction, bringing crowds of people into town. There was always a smell of roasting chestnuts in the air, and the sound of a fairground organ. In the evening, mime artists, stilt walkers and clowns would mingle with the crowds in the lamplit streets, and Santa would turn up on his sleigh.

It was where David and Trisha Pearson should have been on their Peak District Christmas break, not trekking across Oxlow Moor.

A few uniformed officers and PCSOs from E Division had been allocated to Emergency Services Day. The mobile police office was here, with a PC inside demonstrating the old-style fingerprinting technique, which was always popular. A liveried Vauxhall Astra sat with its blue lights flashing and its doors open, so that children could sit in the driver's seat and tap the steering wheel to set off the siren.

'We've located Ian Gullick's vehicle,' said Becky Hurst's voice in his earpiece.

'A blue Transit?' asked Cooper.

'Yes, it was in the town hall car park, close to the market.'

'It's not a priority.'

'I thought not. Uniforms have picked up Gullick, and Gavin's processing him, since he made the arrest.'

'Okay.'

Cooper looked around the park. There was a dog handler too, with his modified Zafira and two dogs in cages at the back a a German Shepherd and a young Springer spaniel training for drug-sniffing work. There might only be two handlers on duty in Derbyshire at any one time, and they covered huge areas in those Zafiras. During the course of a shift they could do up to three hundred miles, a lot of that at night, and mostly on blue lights.

To complete the police presence, an off-duty officer dressed in a tracksuit had set up a couple of punchbags in front of the Ozbox van. Ozbox had been one of the big success stories for Derbyshire Constabulary since it was set up by Sergeant Steve Osbaldeston. It ran six mobile gyms, with two hundred officers volunteering their time to teach boxing skills to thousands of youngsters from problem areas. Old Ozbox himself had got the MBE a few years ago for his work. This was real community relations in action.

'Carol?' said Cooper. 'Are you still on Vince Naylor?'

'We're sitting behind him on Hulley Road.'

'What's he doing?'

'He's in his pickup making a phone call, as far I can tell from here.'

'd.a.m.n, that might mean he's already heard about Gullick.'

'Possibly. What do you want us to do?'

'Nothing hasty,' said Cooper. 'Just stay with him for now.'

'Fine.'

Cooper walked past the E Division Neighbourhood Watch tent. Buxton Mountain Rescue were performing an operation on a scaffolding tower using something called a Petzl nappy. Below the scaffolding stood the BMRT Ford Transit ambulance and Land Rover. Next to them, Derbyshire Cave Rescue Organisation had set up a plastic cave for kids to crawl through with lights strapped to their heads.

He stopped to pat the head of a SARDA rescue dog, a broken-coated collie with odd eyes. It was odd to find the rescue dog here in the park in the centre of Edendale, being fussed by the public. He'd just been thinking that the Pearsons ought to have been here enjoying the Christmas market instead of walking across the moors in the snow. And this dog might have been the very animal to locate them if they'd been lost or injured out there. Despite its appearance, he knew it had the ability to sniff out a human scent over a kilometre away in the right conditions.

'Hold on, it looks as though he's moving again,' said Villiers.

Cooper looked across the park in the direction of Hulley Road, which ran towards the bridge over the river and the traffic lights at Fargate. He couldn't see the white Toyota pickup from here, or the CID pool car behind it containing Carol Villiers and Luke Irvine. He pictured them moving off and pa.s.sing the back of the Royal Theatre.

He began to head towards the corner of the park. A Fire and Rescue team were drawing a crowd by rescuing a mock casualty from an adjacent roof with the extending ladder and cage. He'd probably missed the chip-pan fire demonstration, which always attracted a lot of attention, especially when a firefighter threw water on to the burning pan to ill.u.s.trate the wrong way to deal with it, sending a sheet of flame and smoke shooting up and over the demonstration vehicle.

He'd once seen a fireman playing up to the kids in the audience by wearing a wig that showed long hair peeping out from under his helmet. Then, after the blaze, he pretended his hair had been scorched, and removed his helmet to reveal a totally bald head. That was always good for a laugh.

Cooper looked for the Fire and Rescue Service's Argo Centaur 9500, the 8x8 ATV with fat tyres and a fire fogging system that was normally here for Emergency Services Day. But the Argo was missing today.

Of course, like every other bit of available specialist equipment, it was in demand. It would already be in use out on the moors a not battling a snowstorm like David and Trisha Pearson, but helping to fight those out-of-control moorland fires.

'He's stopping again,' said Villiers. 'Yes, he's getting out. Looks like he's working on a job here. Property on the corner of Hulley Road and Bargate.'

'I'm on my way,' said Cooper. 'Don't do anything until I get there, and we have backup. We don't want another runner.'

'No,' said Villiers. 'Especially as we don't have Gavin here to make the arrest.'

The custody suite at Edendale wasn't one of the newest in the county. If the station ever closed in a further round of rationalisation, the cells might have a sustainable future as a museum of post-war policing. Basic wasn't the word for the facilities. But they weren't designed to encourage a long-term stay.

A few months ago, Cooper and some of his colleagues from E Division had travelled into Staffordshire to view a brand-new custody suite. A main desk like the Starship Enterprise, a phone connection from each cell to the desk, cells steam-cleaned every five weeks. Washbasins, no graffiti. It encouraged personal hygiene, reduced work and minimised risks for staff. They could put legal calls through to the cells.

'Gavin, we need to do the interview as soon as possible,' said Cooper.

Murfin nodded. 'Okay. I'll have a word with Custard.'

Villiers watched him go. 'I hesitate to ask, but ... Custard?'

'The custody sergeant.'

'Oh, obviously.'

Vince Naylor had been drinking when he was pulled in. Stale beer seemed to leak out of his skin in place of sweat. He was a big man, bigger than Gullick, and it took three officers to escort him to the custody desk.

As soon as he was inside, he began to swear and shout. He became frustrated at the way the custody officers ignored him and went calmly about their job taking fingerprints and obtaining a DNA sample.

'What do I have to say to get a response out of you b.a.s.t.a.r.ds?' he shouted.

'We're trained not to react to insulting or abusive words and behaviour,' said the custody sergeant calmly.

'Well f.u.c.k you then!'

'Cell Four.'

'I know you,' said Ian Gullick half an hour later, sitting across the table in Interview Room One. 'Cooper, right? I know you. And your brother.'

'That could be so.'

He laughed. 'Yes, I know you all right.'

Gullick's face was unnaturally flushed, and his eyes bulged slightly, as if he was permanently struggling under some intolerable pressure. He looked like a man unable to escape from the murderer's hands round his throat.

Cooper exchanged a glance with Carol Villiers, who was sitting alongside him with the tapes running. He tried to put some rea.s.surance into the glance.

'We're here to talk about Aidan Merritt,' he said.

'Oh, Aidan.' Gullick sniffed. 'He was always a bit too clever for his own good, Aidan. Read books and things. He thought it made him better than the rest of us. Look how that turned out.'

'Mr Merritt is dead.'

'Exactly.'

'You knew him well, didn't you?'

'We were at school together. Didn't have many interests in common, though. Aidan carried on into the sixth form, did his A levels and all that stuff. He even went to college, I think.'

'So you went your separate ways.'

'Sort of. But, you know, he never moved out of the area. We all thought he'd head off for London. Get away from the rest of us soon as he could. Lots of folk have done it before him, when they got a bit of an education.'

'But he didn't do that?'

'Not Aidan. I don't know why, but he stayed. Got himself a job in Edendale and stuck around. So we b.u.mped into each other quite a lot. You know what it's like a you can't exactly avoid people for long in a place like this, can you?'

'He drank at the Light House, didn't he?' said Cooper.

'Yeah, that's right. Sometimes.'

'You must have talked to him when you saw him in there.'

'We pa.s.sed the time of day. I mean, what do you think? We weren't exactly bosom buddies, though. To be honest, he came over as being a bit weird.'

'Because he read books?'

'That and other stuff.'

'He was a teacher, though. You might expect a teacher to be familiar with a few books. That's what he was interested in, teaching English.'

'Yeah, right. They do say it was something else he was interested in.'

'What do you mean?'

'Well, what else do you get in schools other than books? Children.'

Cooper regarded him coolly. 'There have never been any allegations against Mr Merritt that I'm aware of.'

Gullick shrugged. 'I'm only telling you what people say.'

'That sort of thing is just pub gossip,' said Cooper. 'Because he didn't fit in with your group, he has to be some kind of pervert. What was the problem? He didn't like playing pool? He didn't want to get drunk like the rest of you?'

'He was odd. That's all I'm saying.'

Cooper took a breath, trying to resist the impulse to defend someone he'd never even known. It would only take the interview in the wrong direction.

Villiers stepped in, picking up her cue from his pause.

'What sort of relationship did Mr Merritt have with Maurice Wharton?' she asked.

Gullick swivelled his eyes towards her. Cooper noted with interest that their suspect seemed much more wary of Carol Villiers than of Cooper himself. The threat of the unfamiliar?

'Maurice had a go at him a couple of times for not drinking enough beer. Said Aidan wasn't contributing to the profits.'