All three of them walked down the corridor to the video imaging unit. They filed inside and Mattie shut the door behind him. One of the television screens was on pause and they gathered around it.

Browning leant forward and pressed play. They watched as Stacey Green began to argue with Lewis Waite. She slapped his face and he shoved her, then turned to walk away, only to be grabbed by two of the bouncers. The camera angle changed and there was Stacey again, a bit worse for wear and stumbling towards the toilets, managing to drop her handbag, the contents spilling everywhere.

‘We’ve already watched this.’

‘I know, but I wanted to go over it again. Just in case we missed something the first time.’

As Stacey bent down to pick up her things, Browning said, ‘Watch this corner closely.’

A hand came into view of the camera, passing Stacey some of her stuff. Browning smiled at Lucy. ‘You have to watch closely.’

Lucy and Mattie were both hunched over the screen intently, but Lucy had no idea what she was watching or waiting for. And then she saw it. Stacey must have removed her tights earlier in the night, or had a spare pair, because the hand that was helping her picked them up but didn’t pass them to her. Instead, it disappeared from the screen, taking the tights with it.

‘I think that’s the man who killed her. Either he was very lucky that he wasn’t caught on camera or he knew exactly where the cameras were and knew he would be just out of sight.’

‘How do we know that it’s not Lewis Waite?’ Lucy asked.

‘Because on this next disc Waite is shown being escorted from the club by the bouncers, and the time stamp on that frame is one minute before Stacey drops her bag.’

Lucy looked at Browning. ‘I knew Waite wasn’t right for it, but we can’t just rule him out – this isn’t enough.’

‘No, I agree. It’s not enough to discount him completely, but whoever it is that pocketed her tights is definitely worth checking out, if we can identify him.’

‘Well done – that’s pretty amazing. I don’t know if I’d have spotted that.’

‘Yes you would, boss; you don’t miss a trick.’

She smiled. ‘Right then, we need to find out who this mystery man is. Did you check the cameras before and immediately after she left the club?’

‘I did. People are in and out on their own, in groups, couples.’

‘So near, yet so far. I want every single man that goes in or out tracked down and spoken to.’

Mattie shook his head. ‘What about the town CCTV cameras; don’t they cover High Street? If we check them to see if there’re any lone men in the area we can go back and check the club CCTV to see if it’s the same person.’

Lucy patted his back. ‘I’ve also got something I want to share with you, but I don’t want him to know just yet.’ She pointed in the direction of where Patrick was standing talking on the phone. She lowered her voice.

‘As I told Mattie last night, I’m convinced we’re dealing with a copycat killer. Hang on – I’ll go and get the stuff I just printed out.’

She briskly walked back to the photocopier and grabbed the sheets of paper from the tray. Then she returned to the video imaging room where Mattie and Browning were waiting and shut the door behind her.

‘Until I’m one hundred per cent certain that I’m right, this is between us and Col – when I get him on his own to run the checks. I don’t want Patrick doing what he used to do.’

Browning frowned. ‘What was that?’

‘Years ago, if we were ever onto a lead, had suspects to bring in or just used our brains to work out what had happened at an incident, you could guarantee that if he thought it would make him look good he’d take the credit for it. He’d go to the bosses before we even got a chance and claim it was what he’d come up with. He shafted a couple of my friends big time by being such a smarmy, selfish bastard. Only I didn’t realise until it was too late and they’d been moved to another department. I’m not having him pretend this is all his hard work, because in actual fact it was Toby who came up with it originally.’

Browning looked confused. ‘Who’s Toby?’

‘The new CSI. He came knocking on my door last night with a few newspaper articles and stuff he’d found on the internet.’

‘That’s a bit weird – how did he know where you lived?’

Lucy shrugged. ‘It did unsettle me a bit, but what he said makes perfect sense.’

She began to explain to them what he’d told her and what she’d found herself, and by the time she’d finished both men were staring at her with their mouths open. It was Browning who spoke first.

‘Blimey. That’s fucking odd, but I get it. I really do.’

Mattie nodded. ‘So do I, but what I don’t get is why Toby came to your house to tell you. It’s not right.’

She stared at Mattie. ‘Obviously he thought it was important and he just so happens to be right. I think it’s vital information.’

But he was shaking his head. ‘How did he know this? He’s only been here since the second murder.’

Mattie stopped in his tracks and Lucy felt a lead ball form in the pit of her stomach. Was it a coincidence that Toby had just started working here when the murders began, or something more sinister? She didn’t know.

Mattie gaped at her. ‘You don’t know him! Why did you let him in, Lucy? I don’t like that he knows all this stuff – it’s like he was spelling it out to you. Why would he need to do that? You’re clever. You’d have worked it out for yourself.’

Lucy loved how loyal Mattie was and she knew that normally she was very good, but she hadn’t seen this coming and she wasn’t afraid to admit that.

He continued. ‘I mean, it’s as if he was fed up of waiting for you to come to that conclusion. Why did he need to give you a helping hand? And am I the only one who thinks it’s weird that he knew where you lived? He’s only been here a week – I don’t imagine at any point you’ve spoken to him long enough to give him your address…’

Lucy looked at him. ‘Oh Christ, what if it’s him? What if he’s the killer?’

Browning suddenly interjected. ‘Then I think we should bring him in for questioning; we need to search his house and car. If we find anything that those blue fibres could have come off and can match them back to him it will give us enough reason. In my opinion, he’s just become a very valuable person of interest. Who’s going to arrest him? Us or task force?’

She sat down, the weight of it all crashing down on her shoulders as she ran through their conversation last night. He’d freely admitted he had a fascination with serial killers whilst he was sitting opposite her. She’d felt a little uncomfortable letting him into her house, yet she had. But – and this was the crucial point – was he capable of masterminding all these murders? She couldn’t answer her own question because she knew very well that the sickest individuals could be the nicest person you knew. You only had to look at Ted Bundy, with his good looks and charming personality. Who would ever have guessed that underneath was a man with nothing but complete depravity inside his mind?

‘We still need to find Waite – he might be the one person who actually got a good glimpse of the killer. He may turn out to be our star witness.’

‘Leave Waite to task force – he’s not our priority,’ argued Mattie. ‘I think we need to bring Toby in. Browning and I can do that. He won’t be expecting it – is he in work today? Because that would make it straightforward. Then we can get a search team to go through his house and check for any forensic evidence.’

Lucy picked up the phone and rang Amanda. She answered immediately.

‘Is Toby there?’

‘It’s all about the new boy! I told you, he’s too young for you, Lucy. No, he’s not – he rang in sick.’

Lucy cupped her hand over the phone and mouthed, ‘He’s rung in sick.’

Mattie arched an eyebrow at her.

Amanda continued. ‘Why do you want him? Can I not help you?’

‘No, it’s okay, thanks. I’ll catch up with him later. I hope he’s okay – did he say what’s wrong?’

‘Apparently he’s got a bug. I didn’t answer; it was Jack who spoke to him.’

‘Thanks.’

Lucy put down the phone. ‘Now what?’

‘Browning and I will pay him a welfare visit, make sure he’s okay and doesn’t need anything. Then we’ll bring his arse in for questioning.’

‘I don’t know about this… it might be too dangerous.’

‘Well, then you’ll have to run it by your favourite boss, who will then run it by headquarters. Who will then spend the next six hours assembling a team to go in and get him. Or you could go with the simple option: the two of us can go and knock on his door. He might not even be there – who’s to say that he hasn’t left the country after he paid you a visit last night? He could be on the other side of the world by now, because that’s where I’d be if it was me.’

Browning nodded. ‘There’s also a chance that it’s not him and he’s tucked up in bed with a sick bowl, so it might not even be dangerous.’

She was torn. If they did it the official way it would take hours. Patrick would take command and they would lose momentum. She didn’t want to put Mattie and Browning in any danger, though; she’d never forgive herself if anything happened to either of them.

‘I don’t want Patrick taking over, but I don’t want either of you putting yourself at risk.’

‘Look, Lucy, I’m not being funny but we’re both big boys. We have the element of surprise – Toby won’t be expecting us to come calling. I can pretty much guarantee he’ll come without a fight. If it is him, he killed two women who were both under the influence of alcohol. He shot an entire family in the night – he crept up on the dad from behind and got the others whilst they were asleep. He might be one sick fuck, but he’s not confrontational. He was alone with you in your house; if he’d wanted to hurt you he could have, but he didn’t.’

Browning nodded. ‘He’s right, boss.’

‘You wear your body armour and if there’s any remote chance of it all going horribly wrong you hit your red buttons. I’ll come with you.’

Mattie shook his head. ‘Absolutely not; you’re a liability. He seems to like you – if you’re there and he was to get the upper hand there’s no telling what he’d do.’

Her stomach was churning so hard it felt as if it were about to somersault into next week. Mattie was right: they’d been on arrest enquiries hundreds of times and they both knew how to handle themselves.

Browning sat down opposite her. ‘I’ll make sure the golden boy is safe. If I think it’s too dangerous I’ll pull back and we’ll let the boss man take over. All we’re going to do is go to his house and pay him a visit. He came to yours; we’re just repaying the favour. We can tell him you’ve asked us to come get him because you need to speak to him. It will work like a charm, trust me.’

She nodded. ‘Any sign of danger, you pull out and call for back-up.’

They both spoke in unison. ‘Yes, boss.’