Finn overtook a lorry stationed in the middle lane of the motorway. ‘Do you think this is the breakthrough we’ve been hoping for? It feels like the beginning of the end.’

Kate didn’t want to answer, fearful of once again raising his hopes of justice for Amy, only to have them dashed later. But even she couldn’t explain the coincidence of Wallace Brookes’s face appearing on the footage from the gym. He lived miles away, so there was no reason for him to go out of his way to attend the gym, unless he had an ulterior motive for being there.

‘Should we tell Armitage?’ Finn pressed, glancing from her back to the road.

‘We have nothing yet,’ she cautioned. ‘We need to know for sure before we act.’

‘But what if we’re too slow and he does a bunk? Surely it’s better to arrest him and then find what we need?’

‘Suspects can only be held in custody for twenty-four hours before being charged, and that includes time for interviews, food, solicitor consultation and sleep. If we move without the evidence, we risk allowing him to slip through our fingers. I promise you, as soon as we have something concrete, you can call Armitage. In the meantime, let’s see if there is any proof. For all we know, there is a perfectly reasonable explanation for Brookes having been there.’

Even Kate was struggling to be convinced by her own argument. Yet she’d interviewed Brookes before, and she hadn’t felt he was responsible. Either she’d made a mistake then, or she was making a bigger mistake now.

The phone in her hand erupted to life. ‘Laura? Thanks for calling me back.’

‘Where are you, Kate? I stopped by your place to see how you’re feeling after last night, but there was no answer.’

‘I’m with Finn – it’s a long story – but we might be on to something. I need you to work something from your end today.’

‘I’m not supposed to be in today.’

‘Please, Laura. I need someone I can trust to dig up information on Wallace Brookes.’

‘Who’s he?’

‘Steph Graham’s neighbour in Finsbury Park. We interviewed him as part of the original investigation, but we dismissed him.’

‘And what’s changed?’

She looked to Finn, hoping to God they were on the right track this time. ‘We have reason to believe he had contact with Willow Daniels, which ties him to one of the earlier crimes. I need you to pull up everything you can on him. We’re talking bank accounts, credit cards, criminal record, known family, anything and everything. Understand?’

Laura finished scribbling her notes. ‘Anything else?’

If she was to connect him with all three murders, she needed to establish a link to Roxie O’Brien. ‘See if you can find out his shoe size. There was a male size-ten print left at the second crime scene. It’s not conclusive, but if that’s his size, it would help.’

‘Understood. Okay, let me see what I can find, and I’ll call you with an update in a bit.’

‘Thank you, Laura. And keep your head down. If we’re wrong about Brookes, no one can find out we were looking into him.’ She hung up the phone, the anticipation sending her insides into a swirl.

---

The leisure-centre car park was much quieter than it had been the previous afternoon. Finn dropped Kate at the door, so she wouldn’t have as far to hobble on her crutches. The pain was far greater than the sprain she’d been diagnosed with last week. Deep down, she knew her injury was more serious this time, but to have it reviewed in hospital would waste valuable time she simply didn’t have. She promised herself she would visit hospital once Amy’s killer was behind bars. In the meantime, she swallowed the final two painkillers the doctor had prescribed.

There was no queue at the counter, but there was no sign of Ethan either. Kate smiled warmly at the young woman behind the desk, who couldn’t have been much older than Willow had been. ‘Is Ethan around, please?’

The girl didn’t return the smile. ‘Day off.’

Kate slid her business card across the counter. ‘I wonder if you could help me instead?’

‘What with?’

‘I’d like you to check if a man called Wallace Brookes is a member here.’

The girl blew a bubble with her gum, nonchalance plastered across her face. ‘That badge looks fake.’

It was a mistake to have come in in person. Kate had to tread carefully. She’d been suspended from duty and if Armitage or the supe caught wind of what she was doing they’d probably have her arrested for impersonating a police officer.

‘Is your manager here?’ Kate asked, making her threat clear.

‘Day off,’ the girl replied.

‘What about your security team? I understand there’s someone who monitors the security cameras?’

The girl continued to watch her in silence, waiting to see if Kate would give up, before finally putting a radio to her mouth. ‘Vern, someone at the front desk for you.’ She lowered the radio to the desk, picked up her mobile and started tapping away.

A large man in a navy jumper bursting at the seams waddled up to the counter a few moments later. He sounded out of breath as he introduced himself with a baritone voice. ‘I’m Vern. Can I help you with something?’

‘I’m Detective Inspector Matthews. I’d like to look at your list of members and ask you some questions about your security footage.’

He considered her, a wayward look in his eyes. ‘You know I was going to join the police once.’ He shuffled off, indicating for Kate to follow, and led her to a small, dark room the size of a broom cupboard. He unlocked the door and entered, holding it open for her to follow. Inside the narrow room, there was a desk against the far wall, on top of which stood half a dozen black-and-white monitors and a stack of what looked like DVD players. The chair in front of the desk was tattered, its yellow stuffing pushing through the threads. A computer monitor and desktop PC completed the furnishings.

‘What can I do for you?’ he asked when the door was closed. The room was windowless, and the only light came from a single energy-efficient bulb over their heads.

‘Does that computer link up to the front desk? I want you to see if a particular man is a member.’

He nodded and punched some keys on the keyboard. The monitor flickered to life and a search window with various fields opened. ‘What’s his name?’

She spelt out Brookes’s name as Vern typed it into the search window. A small egg timer span on the screen as it searched, before a new window flashed up stating ‘no results found’.

Kate cursed under her breath. Of course it wasn’t going to be that easy. She sighed. ‘Okay. All of your members have photographs on their member cards, right? Is it possible to look at each male photograph? Maybe I can identify him from that.’

‘It could take some time, love. Our database is shared with a couple of other sites. There will be hundreds.’

Kate checked the watch on her wrist. ‘Can you filter it by age? The man I’m looking for must be in his forties or fifties by now.’

Vern nodded, rolling the mouse around on its mat until a folder of images opened. ‘Okay, here are all our male members over the age of forty. Do you see him?’

---

‘I don’t get it,’ Kate huffed. ‘More than a hundred images and he wasn’t in any of them.’

Vern was leaning against the wall near the door, the mug in his hand cooling rapidly. ‘Maybe this man is not a member. Why are you so sure he is?’

‘He appeared on your security-camera footage in the weeks leading up to Willow Daniels’s murder.’

A wide smile grew on Vern’s face. ‘You’re the one who asked for the videos yesterday, right? Ethan’s friend.’

She tried to smile back, but felt exhausted. ‘That’s right.’

‘And you saw this man on the videos?’

Kate yawned. ‘Yeah.’

He launched forwards, placing his mug on the desk near her. ‘Show me on the video what he looks like. Maybe I’ll recognise him?’

Kate checked her notebook and gave him the date and time of the shot of Brookes. Vern located the relevant DVD case in the cabinet hanging above the desk and loaded the disc into one of the DVD players. He fast-forwarded to the time reference and Brookes’s face filled one of the smaller screens.

‘That’s him,’ Kate gesticulated.

Vern leaned closer to the screen, his navy jumper pressing into her shoulder as he did. ‘Oh, I remember him. But he isn’t a member. He was an engineer sent in to service the water boilers. Yeah, I remember him, well, with a face like that, he’s hard to forget.’

Kate’s breathing quickened. ‘Did you catch his name? Or the name of the company he worked for?’

Vern frowned. ‘It was a long time ago. But there might be a way to check.’ He stretched up to the cabinet over the desk. Removing a new case, he loaded the disc into the next machine. An image of the car park appeared on a second monitor. He spun though until he found what he was looking for. ‘There you go. There’s his van.’

A grey short-base van was parked on the right-hand side of the screen. As Kate continued to watch, she saw a man in overalls, wearing a thick woollen hat, open the rear doors of the van. If Vern was right, Brookes and his van were at the leisure centre the day before Willow Daniels died. She jotted the van’s registration number on her pad, and asked him to make her a copy of the footage, then Kate turned and hobbled out of the room, reaching for her phone as she stepped back into the light.