Jessica had barely got back into her car when Reynolds returned her call. ‘That was quick,’ she said.

‘Yeah, don’t get your hopes up. It’s just to say that the number definitely isn’t publicly available, we’re going to have to stick a request in. I’ll get the paperwork moving tonight but you know what it’s like at this time of year.’

Jessica returned to the station to find the forensics worker had emailed her the rest of the details, including when the call from Benjamin Sturgess’s second phone had been made and how long it had lasted. She crosschecked the dates with when Isaac Hutchings was reported missing and noted the call had been placed somewhere between three and four days before the boy had disappeared. The timing wasn’t damning and proved very little but it was at least roughly in the time frame they would have expected.

Knowing there was little more she could do, Jessica phoned Adam. They had spent Christmas Day and Boxing Day with Caroline at Jessica’s flat but were planning to sleep at Adam’s for the rest of the week. ‘On my way,’ she said. ‘Dinner better be on the table.’

Adam laughed. ‘What do you want?’

‘Just warm some of that turkey up with something. We’ve still got enough to get us through most of the next six months.’

As she drove back to Adam’s house, Jessica couldn’t stop herself from grinning. Many times over the past few years, her life had become dominated by things that were going on at work. She was still determined to find whoever was working with Benjamin Sturgess but, for the first time in a long while, Jessica was actually enjoying her life away from the station.

With another three-day weekend coming up, Jessica had largely expected things to drift into the new year before any details relating to the phone number were passed on. But in the middle of Friday morning, the information arrived. She was sitting in her office when Reynolds walked in with a pad of paper. ‘I’ve got it,’ he said.

‘What?’

‘The name and address of whoever Benjamin Sturgess called.’

‘Anyone we know?’

‘No, but there’s one little snippet which should interest you – our guy’s a teacher.’

Reynolds read out what details he had. Nathan Bairstow taught at a primary school on the outskirts of the city but, perhaps more importantly, his house was on the same estate as Daisy Peters’s. From what they could tell, he was single and lived alone. The information answered at least two of the things Jessica had been trying to figure out. Firstly, he lived close enough to Daisy to have noticed her circumstances if he was looking and, secondly, his position might give him access to the details on the list they had found in Benjamin’s allotment shed. Nothing had been proven yet but the fact Benjamin had contacted Nathan in the days leading up to Isaac’s disappearance was an important breakthrough.

Jessica stood. ‘When are we going?’

‘Jack’s sorting out a team to go with us.’

‘Have we got a photo?’

‘Nothing on file.’

‘Do we know if he’s in?’

‘No idea. The information only came in ten minutes ago and I got one of the constables to sort the rest out. We’ve moved as quick as we can.’

Jessica made a humming noise. ‘What was the DCI like?’

‘Professional. You should apologise.’

It was good advice but Jessica wasn’t ready to give in. ‘I’m not sorry.’

‘You should be. He’s doing his best to protect us while taking a lot of stick from above.’

Jessica knew he was right but didn’t want to admit it. ‘Let’s get going,’ she said, ignoring his point.

The decision had been made to go in softly but with a large backup. Jessica and Reynolds would knock on the door and, as delicately as possible, arrest Nathan Bairstow and bring him to the station. A larger team of officers would be waiting at either end of his road in case he tried to run. The problem with mounting any kind of big operation was the amount of attention it would attract from regular members of the public. It could make things complicated for any number of reasons, from having civilians in the way, to – on certain notorious estates – giving the suspect a head-start. The area Nathan lived in was perfectly respectable and Jessica didn’t envisage any problems there but, because so many people would be home from work in the week between Christmas and New Year, there was a much greater chance of unwanted attention.

Jessica and Reynolds travelled in his car, while the rest of the officers took unmarked vehicles. A secure van would be minutes away if it was required. The roads seemed to be full of families packed into cars stuffed full of bargains picked up in the sales. The traffic was worse than usual during rush hour, which left Jessica shuffling around restlessly in the passenger seat as the inspector drove.

Eventually, Reynolds parked his car a few doors down from the address they had for Nathan Bairstow. As the two officers sat waiting for confirmation that the rest of the team were in place, Jessica scanned the surroundings. Piles of slushy ice, snow and frost had been edged to the side of the road, with thin lines running along the centre of each carriageway, showing where cars had been moving over recent days.

Reynolds broke the silence. ‘It’s that one,’ he said, pointing towards a red-brick semi-detached house to their left, but Jessica had already worked it out. There was a gold foil ‘Merry Christmas’ banner hanging in the window and a string of fairy lights switched off. Aside from that, the house was as plain as could be.

Jessica tried to work out the distance from where they were to Daisy Peters’s house. The whole estate was a complex maze of one main road going through the middle, with a large number of streets funnelling from it. To drive from Nathan’s house to Daisy’s might take ten minutes simply because of having to weave in and out of parked cars. From where she was sitting, Jessica could see at least two pathways surrounded by overhanging branches that led from this section of the estate into another. If you had a good enough knowledge of where the various ginnels led, there was every chance you could navigate the complicated layout quickly and, more crucially, unnoticed.

The inspector’s mobile phone rang. After the briefest of conversations, he put it back in his pocket. ‘Let’s go.’

Jessica opened the door and stepped over one of the piles of ice, making sure she was extra careful with her footing. Their footsteps crunched as they walked to the end of Nathan’s pathway. Reynolds started to walk towards the door but Jessica stopped him.

‘He’s not in.’

The inspector turned around, looking puzzled. ‘What?’

Jessica pointed to the driveway on the other side of a small patch of frost-covered grass. It had been shielded from their view while they were waiting in the car. ‘Look at the drive,’ she said. ‘The edges have the same slush that’s everywhere else but there’s a clear patch where a car usually sits. You can see the tyre tracks across the pavement.’

The inspector looked where she was pointing and nodded. ‘We’ll try it anyway.’ They approached the door and rang the doorbell. After a few seconds with no sign of any movement, Jessica approached the window, peering inside.

‘The curtains are open,’ she said. ‘Either he’s been around recently or someone’s been coming in and doing it for him. What do you want to do, ask the neighbours?’

Reynolds started to walk away from the house and beckoned for Jessica to follow. ‘Let’s wait for a bit. It looks like he’s been around today and there are so many people out shopping, he might have nipped out for an hour. He would have seen everything on the news about Benjamin Sturgess so if he was going to make a run for it, he’ll already be gone.’

It sounded to Jessica like a relatively sensible plan, albeit one that would involve them sitting in a freezing-cold car.