Mo was right. In court, Bolt had exaggerated the strength of Oldham’s ID of the photo, but he was sure it had been the right thing to do. ‘You said yourself you believe Hope’s guilty. I think he is too. So what do you suggest we do?’

‘Wait for the DNA results. Then we’ll have our proof one way or the other. In the meantime, we’ve got him locked down with surveillance, so it’s not as if he’s going anywhere. If we go charging in there now, boss, and it later turns out in court that we obtained the search warrant under questionable circumstances, the case might be thrown out.’

‘Not this time. No judge is going to dare chuck out the case against Hope on a technicality, not when he’s killed that many people. Come on, Mo. We’re doing the right thing.’

Mo sighed. It was clear he wasn’t convinced, which surprised Bolt. He wasn’t usually a by-the-book man, but then he had a family to support and mouths to feed. He couldn’t afford a blemish on his record, whereas for Bolt it was a different story. He’d become more fatalistic of late. If he had to risk his own career to put down serious criminals, then so be it.

Knowing there was no point continuing the discussion, he opened the car door. ‘Let’s get this over with before he gets back.’

They crossed the road and walked to Hope’s front door in silence. His house was one of the more cared-for of those in the street. The door and windows looked new, and the small front garden was neatly tended, with the grass on either side of the path freshly mowed. It was a warm autumn day, and plenty of houses had their windows open, including the ones on either side of Hope’s, suggesting that – although the street was empty – his neighbours were at home. This meant they were going to have to be very careful. The last thing they needed was for someone to spot them breaking in and either call the police, or alert Hope to what was going on.

Both Bolt and Mo Khan were experienced housebreakers. During their time in the National Crime Squad, the Serious and Organized Crime Agency, and most recently attached to Counter Terrorism Command, they’d had to make more than their fair share of covert entries into the homes of suspects, usually to plant bugs in them. Hope’s front door had three separate locks, all of which were on, but it still only took Bolt about a minute and a half to pick them. As Bolt worked, trying to look as casual as possible, Mo stood slightly behind him, obscuring the view from the street. They were both banking on the fact that because they were dressed in suits and didn’t look like burglars, they wouldn’t attract attention. But they needn’t have worried. As Bolt opened the door and stood back, he gave a quick glance left and right. The street was still empty and no one appeared to be at their window. It was clear they hadn’t been noticed.

The house was just as neat and tidy inside as out, which, in Bolt’s experience, was a rarity with criminals, who tended to be a slovenly bunch. ‘Blimey, I wish my place was as well-kept as this,’ he said, walking through the hallway into a narrow kitchen with worktops running down one side. A single, half-drunk cup of tea by the sink was the only thing out of place. The surfaces were spotless and a number of pots and pans hung down from hooks on either side of an old gas cooker. Bolt checked the cupboards and saw that they were well stocked with a variety of ingredients and condiments. Leonard Hope was clearly interested in cooking. Bolt shook his head. Even after years as a police officer, he always found it hard to reconcile the fact that sadistic, sociopathic killers like The Disciple – individuals who thought nothing of torturing their fellow human beings to death for pleasure – could have harmless, mundane interests like everyone else. But, of course, it was this apparent ordinariness that often made them so hard to identify.

While Mo started in the living room, Bolt went through every cupboard and drawer in the kitchen. According to the pathologist who’d carried out the autopsies on all The Disciple’s victims since he’d started his current round of killings, the same weapon had been used in three of the attacks, and it was this that Bolt was most interested in finding. The weapon he was looking for was a knife with a serrated edge and an eight-inch blade. Two of the teeth about an inch down from the tip were slightly bent to the left, which meant it shouldn’t be too difficult to identify it if it was here. Bolt had once done a search of the flat of a young gang member who lived with his mother, after they’d arrested him for stabbing a rival to death, and he’d found the murder weapon, which turned out to be the kid’s mother’s carving knife, in the kitchen knife rack. He’d washed it clean of blood and simply put it back. When asked later why he hadn’t tried to get rid of it, he’d replied that his mum would have killed him. Apparently, she liked that knife and was always on at him for borrowing it. But he had a feeling that Hope would be a lot more careful than that.

They worked through the house, moving quickly. Because the place was so tidy, it didn’t have a very lived-in feel, but it didn’t look much like a show home either. The furniture was old-fashioned and worn, and most of it had probably belonged to Hope’s mother. It was the same with the pictures on the wall. They were old prints of animals and country scenes and reminded Bolt of the ones in his grandparents’ old house. There were no photographs on display anywhere. In fact, there wasn’t much of anything – no books; a handful of CDs and DVDs; a few stacks of old utility bills – and certainly nothing that might suggest that Leonard Hope was a prolific and extremely dangerous serial killer. The only computer equipment he owned was an Acer laptop in his bedroom, and there was nothing untoward in the recent Internet history. He liked to visit news sites, and several of the pages he’d viewed referred to the police hunt for The Disciple, and the murders of George Rowan and Ivana Hanzha, but then he also liked to visit cookery and DIY sites. Officially, the terms of the search warrant didn’t allow for a search of the hard drives of any computer on the premises, but Bolt made a copy of the hard drive anyway, figuring he could at least trawl through it unofficially.

Every five minutes, he received a radio update from the DS running the current surveillance team. Hope was still making deliveries, and none of the team knew how many more he had to make, but in the two days they’d been following him, he’d been back at 6.01 and 6.06 p.m. respectively, which meant they had to keep an eye on the time.

As it happened, it took Mo and Bolt barely half an hour to cover the whole house. As well as searching in every available bit of storage space, they’d also checked for any false walls, loose pieces of carpet and floorboards, under which a knife could be concealed, but without success.

‘Nothing,’ said Mo, joining Bolt at the top of the stairs. ‘Either he’s very careful, or he’s innocent.’

‘He’s not innocent,’ said Bolt, who was having difficulty keeping a lid on his frustration. He’d been expecting to find at least some clue to Hope’s guilt, even if it was just a few books on devil worship, or some perverted porn in the Internet history of his laptop. Very few serious criminals hid all traces of their guilt, especially those who had no obvious reason to expect a visit from the law. He exhaled loudly. ‘There’s still one place left to look.’ He pointed to the hatch above their heads that led into the loft.

Mo looked at his watch. ‘Have we got time? It’s 5.15. He’s not going to be that much longer.’

‘He’s in Hayes at the moment, according to Grier, so even if he turned round and came straight back here, he’d be a good half hour. We’ve got time.’

‘Did you see a ladder in here anywhere? Because I didn’t.’

Bolt frowned. ‘No, I didn’t. And we searched the place well enough.’