Alex stood in the corridor outside the room in which Leah Cross lay hooked up to machinery. Just a few blocks away, in the intensive care unit, Amy Barker was still battling for her life. If there was any truth in Tom Stoddard’s claim that Leah was involved in the drug dealing, Alex would have to fight the urge to drag the girl down the corridor and make her face up to the suffering her actions had caused another person. And not just Amy, Alex thought. Maybe she should leave Leah Cross with the girl’s mother, let Ms Barker decide what to do with her.

But perhaps she was jumping to misguided conclusions. All she had was Tom Stoddard’s word, and that had already proven unreliable. For now – and until there was evidence of anything to the contrary – Leah was a victim. Just like Keira. It seemed entirely plausible that Tom would attempt to incriminate his housemate in an effort to divert attention from himself. The two were supposed to be friends, but Alex doubted friendship meant very much to Tom.

‘Has she woken at all yet?’ she asked one of the nurses, an overweight, stern-looking woman whose bleary eyes and abrupt manner suggested her shift had started the night before and she was long overdue home. She breathed heavily and noisily, her uniform straining across her heavy bust and her chest rattling with every inhalation. She was hardly a poster girl for healthcare, Alex thought.

‘Not yet.’

‘How is she otherwise?’

‘Bruising to the torso consistent with cracked or broken ribs,’ the nurse told her. ‘Head trauma, although the doctor says it’s unclear to what extent at the moment. Do you know who hit her?’

Alex looked to the door of Leah’s room and ignored the woman’s question. ‘Has her family been informed?’

The nurse shook her head. ‘She doesn’t seem to have any contacts for them. The officers who were here last night couldn’t find anyone in her phone – no one listed as “Home” or “Mum” or anything like that.’

Alex nodded. ‘I’ll chase it up.’

‘I’ll be along the corridor if you need anything.’

The nurse left her alone outside Leah’s room. Alex pushed the door open and sat on the hard armchair at the side of the bed. The girl just appeared to be sleeping, her eyelids heavy and her breathing steady. Her left eye was shadowed in bruising that looked too old to have been inflicted the previous evening. It looked more like the result of a fight than a hit-and-run. Her right arm was resting above the hospital blanket, and on her shoulder Alex could see more bruising, soft and green-tinged, peppered across the pale skin. Fingertip bruising.

She leaned closer, checking the pattern of the marks. What had happened to this girl before the car had hit her last night? she wondered.

Her thoughts roamed back to Tom Stoddard. Did she think him capable of drug dealing? Yes. Did she think him capable of violence? Without a doubt. Had he been driving that car the previous night? He didn’t own a car, but he had a licence and might have had access to someone else’s. He hadn’t left the station until late the previous evening, but there had been a couple of hours between then and the time Leah was hit. But why would he do it? And was it connected to the death of Keira North?

They would need to find out where Leah Cross had been the previous evening, who she had been with before she arrived back on Railway Terrace. The eyewitness who had left the shop up the road shortly before the incident had claimed Leah had been walking towards the house, which suggested she was making her way home rather than heading out anywhere.

As she looked at the sleeping girl, Alex found herself consumed with a curious mix of pity and frustration. She remembered how Leah had cried for Keira during her interview at the station on Monday. She had seemed vulnerable in so many ways, yet there was something about the people in that house Alex just didn’t trust. Tom and Leah had been arguing at the house the previous day, shortly before Alex and Chloe had taken Tom to the station. Had it been about drugs? And if she’d known something about his dealing, did she also know the truth about Keira North’s death?

The two girls had been friends, or at least Keira had apparently thought as much. The photo collage pinned to the wall above Keira’s bed had featured an array of images of the two girls together, arms circled around one another, faces smiling for the camera. Surely if she knew something about the death of her friend, Leah wouldn’t be keeping it from the police?

Alex stood from the chair. If Leah had been lying to them, she was determined to find out why.

She left Leah’s room and made her way out of the hospital and back to the car park. The university was just a couple of miles from the station – she would pass it on her way back to Pontypridd. It seemed an appropriate next stop. Perhaps the admin department there would be able to throw some light on Leah’s background. Someone had to have a home address and contact number for her.

South Wales was still bathed in an uncharacteristic wash of blazing sunlight, and as Alex headed away from the hospital in Llantrisant and back towards Pontypridd, she felt herself almost calmed by the warmth that fell over the car. It had a deceptive quality, offering the false impression that everything was right with the world. She glanced at the Bluetooth screen on the dashboard. The clock read 11.10. She wondered whether her mother was awake, or even if she would wake at all that day.

Perhaps she should call, she thought. But she didn’t.

She joined the stretch of A470 that would take her to the university campus just outside Pontypridd. It had undergone a recent revamp, the former University of Glamorgan having merged with the University of Wales in Cardiff to create a new University of South Wales with campuses in Cardiff, Newport and Treforest. The Treforest complex was a sprawl of buildings that could be seen from the main bypass; a mix of old and new, characterised by a series of huge white blocks like giant Lego pieces adorning the hillside. Alex veered left off the dual carriageway to meet the roundabout at Upper Boat and headed left towards the new road that would take her to the campus.

A secretary at the main reception pointed her in the direction of the English department, which was located in one of the university’s older buildings. The campus was eerily quiet at this time of year, the majority of students having already left for the summer. There was a small reception area within the department building’s foyer; here, Alex pressed the bell and waited for someone to come from the office. She introduced herself and showed her ID, explaining that she was looking for the home and family contact details of a student who’d been involved in a hit-and-run incident.

‘Is she OK?’ the woman asked.

‘Too soon to tell at the moment.’

‘I hope she’ll be all right. Do you want to come through?’ The woman moved from the desk and tapped a code that would allow Alex access to the office. She took the chair the woman offered her and waited as she logged on to the department’s database.

‘The system’s so slow,’ the woman said, talking more to the computer than to Alex. She tutted as she waited for the page to upload. ‘OK. Leah Cross, you say?’

Alex nodded, and the woman typed the girl’s name into the search bar.

‘Here we go.’ She turned the screen so that Alex could get a better view. There on the screen was a photograph of Leah, an image presumably taken on the department’s registration day at the beginning of the previous academic year.

‘I’ll print this off for you, shall I?’

‘Please.’

Alex glanced at the address on the screen as the woman set about her task. Newton Abbot, Devon. She had detected a hint of an accent in the girl’s voice, though it wasn’t strong.

The woman stretched awkwardly across the desk to retrieve the sheet from the printer.

‘Thanks,’ said Alex, standing. ‘I think this should be all, but if there’s anything else, I’ll be in touch.’

‘Of course. I hope she’ll be all right.’

Alex left the building and reached for her mobile phone from her pocket. She keyed in the phone number provided on the printout as she walked back to the car park, waiting until she was inside the car before making the call. It was a landline and it rang for a while before someone answered. A woman’s voice greeted her.

‘Hello,’ Alex said, ‘this is Detective Inspector Alex King, South Wales Police. I’d like to speak with Mr or Mrs Cross if they’re available.’ There was a pause at the end of the line, and for a moment Alex thought the connection had been lost. ‘Hello?’

‘Hello,’ the woman said. ‘Sorry … there’s no one here of that name.’

Alex glanced at the printout in her hand. ‘I’m calling with regard to a Leah Cross.’

‘Sorry,’ the woman said again. ‘I don’t know that name. I’m afraid you’ve got the wrong number.’

Alex apologised and ended the call. She checked the number she had typed into her phone alongside the number that was printed on the page. She hadn’t made a mistake: they were a definite match.

Why had Leah Cross provided the university with false contact details?