Guiltily, she’d been imagining Cooper waiting at the derelict building for hours in the cold and the darkness, hoping for his coup, while she was busy doing the real work here at Bowden.

But if it was true that Shaw hadn’t killed George Redfearn, who had? And who was Cooper meeting in Hartington?

Though the tall, athletic figure was familiar to Cooper, she was no longer the young woman who’d sat nervously in Interview Room One staring at a cup of cold coffee. He couldn’t imagine this woman being intimidated by her surroundings. Her hands were steady now and the rings on her fingers glinted in the glare of a rocket as she stood in the darkness of the abandoned factory.

‘Poppy,’ said Cooper. ‘I wasn’t expecting you.’

‘I’m sorry.’

Cooper peered into the gloom, trying to make out her face. ‘What for?’

‘Everything, I suppose. It wasn’t meant to be like this. It all went wrong.’

There was no light in here, except for a few patches of greenish light from the fog-shrouded moon filtering through the skylights in the roof. Poppy Mellor stood on the edge of one of the rectangles of light, making the shadows around her seem so much darker.

‘Are the rest of the group here?’ asked Cooper.

He looked round, but could see nothing in the darkness. It was another of the large storage areas. The low ceiling and heavy pillars seemed to press in on him and made him feel claustrophobic, though he knew the room must be extensive.

Poppy didn’t answer him. It was as if she weren’t really listening, but just wanted the opportunity to talk.

‘The group have been like a family to me,’ she said. ‘Closer than my real parents or my brother. And just like a proper family, I didn’t really choose them.’

Was she armed with something? Her right arm was pressed too close to her side for him to be sure. Cooper realised he would have to let her talk. He needed her to stay calm and relaxed, and then he might find out what was going on. He also needed time for his back-up to arrive.

Cooper glanced nervously around again. If back-up was going to arrive.

‘Yes. We just came together for this one purpose. It was almost random. We talked to each other all the time on those walks. We talked like I’ve never been able to talk to my dad.’

‘They were loyal too,’ said Cooper.

‘You’re right. They were. None of them gave away the fact that I was there at the bridge, did they?’

‘No. We accepted your story completely.’

‘Thank you.’

She spoke as if it were a genuine compliment.

‘So what did happen at the bridge?’ asked Cooper.

‘It was bad luck. The fact is, Sandra was out of control that night. I don’t know what she was on exactly, but she was totally out of her head. She began to run around in the woods like a crazy woman. Then she came after me and chased me towards the bridge. She scared me. I thought she was going to do me some harm. God knows what she was thinking, but I’m sure she was hallucinating. The others had no idea what was going on, though. We were supposed to be quiet and not draw any attention to ourselves. When they heard all the commotion they didn’t know what to think.’

‘They imagined someone else must be there,’ said Cooper.

‘Yes, exactly.’

‘And that would have ruined the plan.’

Cooper felt his phone buzz in his pocket. He reached for it slowly, but Poppy backed away again and he lost sight of her in the shadows.

‘Sandra caught me near the bridge,’ said Poppy. ‘I seriously thought she was going to do something bad to me, she was so nuts. I think I must have screamed. Jason says he heard a scream anyway. I suppose that must have been me. Though Sandra was making plenty of noise too, crashing about in the trees. But then she seemed to start coughing or choking and she fell on the ground. I had no idea what to do. I thought she was still messing around.’

‘And no one came to help you?’

‘Yes, Jason did.’ Poppy moved her head sideways so that he couldn’t see her eyes. Was she looking towards someone who stood in the darkness? Or was the gesture merely theatrical?

Cooper moved too, trying to maintain eye contact. Perhaps he ought to arrest her right now. But what had she admitted to, really? Perverting the course of justice? Conspiracy? There wasn’t much of a case against her. He needed to know more.

‘It was lucky I wasn’t relying on Rob,’ said Poppy. ‘He’s not the bravest of people.’

‘What happened to Sandra?’ persisted Cooper.

Poppy sighed. ‘She should never have come out with us on something like that. We didn’t know she had a heart condition.’

‘I don’t think she knew either.’

‘If she had a family history of heart disease, she ought to have gone to her GP for a review. I bet she was a prime candidate for heart disease. A bad diet, smoking, too little exercise, a family history…’

‘So. At some point on this particular evening she simply dropped down dead in front of you,’ said Cooper.

‘Pretty much.’

‘And what did you do?’

‘I’ve got to admit, I had no idea what to do. I was about ready to panic, to be honest. But Jason said he’d done a bit of first-aid training. He tried CPR. You know, pressing on her chest, mouth-to-mouth, and all that.’

‘But no one called an ambulance, did they?’

‘No. Well … no, we didn’t.’

Cooper was silent for a moment. ‘No matter how long Mr Shaw performed CPR, it was pretty useless without defibrillation, which is what actually restarts the heart.’

‘That’s what I said to Jason. I mean, we both knew that Sandra was dead. It was so obvious. There was no way she was going to be brought back to life. Right in those first few seconds, she was dead. She was already a ghost.’

Cooper shivered at her choice of phrase. The factory had made him feel uneasy as soon as he’d entered it. If your imagination ran in that direction, you might think there were phantom presences here, the spirits of the former occupants imprinted in the walls. But his senses were warning him of whispers and movements in the darkness. He couldn’t tell yet whether they were real or illusory.

‘We both panicked a bit, then,’ said Poppy. ‘Jason had touched her hat and her torch, so he took those away with him, in case of fingerprints. Then we rolled her body off the bridge. Her head hit the rocks, which was a bit nasty. But she wasn’t feeling any pain by then, was she?’

She was actually appealing to him for reassurance.

‘No, Poppy,’ he said.

‘It was funny, but it was only when I got home that I thought about her mobile phone. But it must have been in the river, I suppose. I dropped my phone in water once. It didn’t work too well after that.’

Cooper took a cautious step towards her, but she noticed and backed out of the light. That was worse. Now she was almost invisible and he was the one standing directly beneath the opening, bathed in the odd light. He could see the green tinge on the skin of his hands, like the discoloration of flesh after death.

‘Poor Jason was upset,’ said Poppy. ‘He was quite keen on Sandra. He likes them a bit weird, I think.’

Cooper could have kicked himself as he listened to her story. He’d noticed all those people coming forward and telling him part of the truth, as if they’d been told to do that. The Nadens, Jason Shaw, even Brendan Kilner. But he’d never thought to himself: And what about Poppy Mellor? She’d come forward voluntarily and appeared to be a willing witness. But she’d only told part of the truth too.

Yes, she’d been clever in some ways. Yet she was so young, so inexperienced about life. And about people too.

‘And George Redfearn?’ he said.

‘Unfortunate. But it was just like Sandra’s death.’

‘No.’ Cooper shook his head. ‘You can see a heart attack coming. It’s there in the tests. It’s in the blood. But this is different. You don’t see a murder coming.’