The mood in the incident room was sombre. The idea that two children might be responsible for the horrific series of crimes they were investigating was something none of the team had prepared for. None of them had ever encountered a case in which children had been the suspects. A search for Keeley and Tyler had begun, though Alex knew they had to tread carefully. With both suspects being minors, no details could be released to the press or on social media. Any leak of information might later jeopardise a trial, and after everything else that had happened, watching this killer duo get away with their crimes was something Alex wasn’t prepared to risk. It meant they would be unable to ask for help from the public, which in turn meant the job of finding the pair would be made all the more difficult.

Did Tyler know about his father’s death? Alex wondered. And an even more chilling thought … was he responsible? It seemed anything was possible now.

Jake had been sent with other officers to search the home of Keeley Coleman. A warrant had been granted quickly, and under Alex’s instructions Sian was to be kept unaware of the suspicions surrounding her daughter. The importance of it staying that way had been emphasised to everyone on the team. If Sian knew where Keeley and Tyler were, there was a chance she might protect them. And there was no doubt in Alex’s mind that the two teenagers were together somewhere.

She and Chloe sat at Chloe’s desk in the incident room.

‘Do you think Sian knows about all this?’ Chloe asked.

Alex shook her head. ‘I doubt it. But if she finds out, there’s no knowing how she’ll react. She’s already got one kid in prison, remember.’

‘So Tyler broke into his own father’s shed to take the petrol can? Surely he would have known it might incriminate his dad?’

‘Perhaps Keeley did it. It wouldn’t matter to her, would it?’ Alex stood and looked at the board. ‘Tyler’s clumsy,’ she continued. ‘He attacked Corey Davies alone and he messed things up. My guess is that it’s probably his fingerprints that were lifted from the front door of Doris Adams’s house. The fact that he left his phone behind at his grandmother’s house suggests he’s disorganised. My bet is that Keeley is the brains behind all this.’

The irony of her phrasing wasn’t lost on her. The kind of brain that could plot and orchestrate such brutal and senseless attacks was the type she knew she would never comprehend, regardless of how many years’ service she might give. Grown men had scared her. Child killers would haunt her.

‘Shit,’ she said. Her own words echoed, taking on a greater meaning than she had intended.

‘What?’ Chloe asked.

‘It wouldn’t have mattered to her,’ Alex repeated. She turned back to Chloe. ‘What if Keeley killed Gavin?’

‘A teenage girl against a grown man?’ Chloe asked sceptically.

‘If Keeley’s responsible for the other deaths, we’re not dealing with a normal teenage girl. Two knives, the pathologist said. He didn’t stand a chance.’

‘Why would she kill her own boyfriend’s father? The other victims weren’t known to her. She would have known Gavin, or known of him at the very least.’

Dan approached them. ‘Listen.’ He held up Tyler’s phone. A clip of the song ‘Kathleen’ played; the same clip they had heard on the 999 call recording. The words ‘impractical’ and ‘death’ were unmistakable now. ‘It’s stored as the ringtone for Keeley’s number.’

‘So what are we thinking?’ Chloe asked. ‘They beat up Gary Peters, the fire was started, and then what? Tyler had a change of heart and called 999?’

‘Looks that way perhaps,’ Alex said. ‘He disappears and Keeley calls him, wondering where he is. He’s smart enough to make the call from a phone box rather than from his mobile, but not smart enough to turn his own phone off while he’s doing it. She inadvertently led us to them.’

‘Either that or Tyler made the call because they wanted to watch emergency services turn up?’

‘Could be.’ Alex sighed. ‘Anything’s possible now.’

‘Be interesting to see what shows up on Sian Foster’s laptop. If she’s got a bit more about her than Tyler, Keeley won’t have done anything from her own phone, will she? She’s been a lot cleverer at covering her tracks than he has. If she’s the one who ordered that skeleton outfit, it had to have been done somewhere else.’

‘What if he told his dad?’

‘Tyler?’

‘You just said he may have made that 999 call after having a change of heart. He was feeling guilty enough then to alert the authorities.’ Alex pressed her fingertips to her lips. ‘Did he need to confide in someone … someone who wasn’t Keeley?’

‘You think he told Gavin, and Keeley found out about it?’

‘Makes sense, doesn’t it? Gavin wouldn’t have come to us. He wouldn’t have been able to report Keeley without incriminating his own son. You okay?’ Alex looked at Dan, who had fallen silent beside them. He didn’t appear to have taken in any of the conversation. He was still holding Tyler’s phone and had been scrolling through its contents, but had stopped at something. His face had paled.

‘What’s the matter?’ Alex asked.

Dan held the mobile up. ‘My daughter’s number. It’s stored on his phone.’