Whitmarsh was one of eight high security prisons in the country that housed category A inmates who posed a danger to the public. After a spell in Rampton Hospital following his conviction, and despite the viciousness of his crimes, Shaw had been deemed of sound mind and he was transferred to Whitmarsh to spend the rest of his sentence at Her Majesty’s pleasure. The shabby interview room at the prison was a place Anna had become depressingly familiar with, but still she found the wait disquieting. Previously, Shaw had always been in the room waiting for her whenever she’d visited. Not today.

It was Dawes’ first visit to Whitmarsh and he looked around at the grey walls and the bolted-down furniture and wrinkled his nose.

‘There’s no ventilation in here,’ he said. ‘Smells like a squirrel’s armpit.’

‘I’ll take your word for that, Sergeant.’

Finally, a door clanged open and Shaw appeared, handcuffed, flanked by two prison officers. When they had him seated and shackled to the floor, one prison officer exited. The other sat at the back of the room, his face composed and blank.

Shaw sat and looked from Anna to Dawes and back again. He leaned back in his chair and said, ‘Who’s your minder, Anna?’

‘This is Sergeant Dawes, Hector. He’s helping me with the case.’

‘Good listener, is he?’

‘The sergeant works in major crimes. He has a lot of experience.’

Shaw nodded slowly. Anna read it as tacit acceptance and she frowned. This, too, struck her as unusual. Shaw’s intolerance of other police officers had been a feature of their relationship. She looked at him carefully. He’d lost weight and his eyes looked puffy from lack of sleep. ‘Are you well, Hector?’

Shaw tilted his head. ‘No, I’m not. Doc says I’m anaemic. They’re running tests.’

‘I’m sorry to hear that.’

‘If you are, you’re in the minority.’

‘Hector, we’re here to talk to you about Abbie.’

Shaw’s eyes narrowed. The last time she’d mentioned Abbie to him, it hadn’t been well accepted. A throwaway remark by the officer she’d been with, a DI called Becker from Sussex police, resulted in Shaw, despite his handcuffs, knocking the man over and trying, unsuccessfully on that occasion, to bite the man’s neck.

‘Why?’ he said.

‘The body we uncovered from the shallow grave you took us to belongs to a boy called Jamie Carson. We now believe he, too, was a Black Squid victim. He left drawings and a message which, though not meaning much to the investigators at the time, suggests to me that he’d been targeted.’

Shaw watched her, unmoving as she continued.

‘We believe Krastev had a role to play in all three victims so far. Abbie included.’

Shaw frowned. ‘I already told you that.’

Anna nodded.

Shaw’s eyes narrowed further. ‘But there’s something else, isn’t there?’

Dawes shifted in his seat. Whether it was surprise at Shaw’s sharpness, or some too tight boxer shorts, it didn’t matter. Shaw threw him a glance and then smiled. ‘You need to work on your poker face, Sergeant.’

‘Krastev, masquerading as Petran, was working on the reconstruction of Ryegrove – a medium secure unit adjacent to the spot you took us to, set back from the railway line.’

Shaw looked away and let out a snigger before looking back. ‘Chudovishtna kushta.’

‘What?’ Dawes said.

‘It means monster house in Bulgarian,’ Anna said, but she kept her gaze on Shaw. ‘We’re trying to piece together exactly what Krastev’s role might have been in what happened to Jamie Carson.’

The smile slid from Shaw’s face like egg off a greasy plate. ‘He called himself a facilitator. He was supposed to help with the final act. Make it easy for the victims. But I didn’t believe him. I think these kids went along with it but at the end, the very end, I think Krastev did the pushing.’

Dawes sat up. ‘You think he killed Carson?’

‘Carson, Abbie and others. They were just kids who found themselves alone with a monster in a place none of them should ever have been. I made him tell me what he did to those kids before they topped themselves. I made him tell me what he did to Abbie.’

Anna glared at Shaw. ‘There’s nothing in the report—’

‘That’s because there wasn’t enough of her left for the pathologist to find the evidence. But I knew.’

‘Jesus,’ Dawes said.

Shaw sent him a slow, reptilian look. ‘He wasn’t there. Never fucking is.’

‘You never reported this,’ Anna said.

‘Come on, Anna. Who’s going to believe me, the rabid killer?’

‘I do,’ she said.

‘This Krastev, he’s the Black Squid, then?’ Dawes said.

‘No. He was nothing more than a blunt instrument. Someone else did the planning. Someone much brighter than Krastev. Someone who covered his tracks.’

‘The others… your other victims, they didn’t tell you who it was?’

‘No. They didn’t know. If they had, they’d have told me and he’d be dead now, too. And there’d be no more kids throwing themselves under trains or off cliffs.’

Anna sat forward. ‘You’re sure these recent cases are linked?’

Shaw nodded. ‘Yeah. He’s just found a different way, a better way. For a start, there’s no Krastev anymore. But technology’s better. And this bastard is smart.’

Anna wanted to get back to Abbie. ‘So you think the Black Squid arranged for Abbie to meet Krastev at Cayton Street and he assisted her—’

‘He killed her.’

‘And killed her there.’

Shaw’s mouth became an ugly slash in his face. ‘She was confused. Just a messed-up kid. These bastards knew that.’

Dawes said, ‘None of this helps us with Alison Johnson.’

Shaw’s eyes widened. ‘She the other body, is she?’

Dawes looked momentarily stricken but Anna shook her head and said, ‘I was going to tell you. She doesn’t fit the profile. Older, a nurse in the unit—’

‘So, she’s a break in the pattern?’

Anna nodded, astonished again at how quickly Shaw could follow her own reasoning. She remembered their meeting in Sussex when Shaw first mentioned Krastev’s reference to the monster house. Something he’d said then. ‘You said Krastev was reluctant to tell you about Jamie Carson and where he was buried. That he needed a lot of persuading. Why do you think that was?’

‘He was hiding something. Something he was prepared to suffer pain for rather than tell me. Wouldn’t even sing when I chucked the first shovel full of soil on the plastic sheets I’d wrapped him in.’

Anna grimaced. Shaw spoke about his murders so casually. ‘Why?’

‘Maybe because he was more scared of telling me than he was of what I’d do to him. That’s a powerful fear, don’t you think?’

Anna held Shaw’s gaze. The colour in his irises seemed to move like oil. As with everything he said, it hid a subtext. Something too obscure to read.

‘What happened to Krastev?’ Dawes asked.

‘I let him sleep on it. Under six feet of earth. Unfortunately, when I dug him up the next day, his heart had given out. Maybe something to do with all the bleeding he did. Never got a chance to finish his story.’ Shaw grinned. ‘But I had enough to be getting on with.’

‘And you can’t think of any reason why he’d kill a nurse?’ Dawes said.

‘I can think of several. The bastard was an animal. But it’s not what’s important.’

Dawes took offence. ‘Her relatives think it is.’

Anna kicked him under the table. ‘What do you mean, Hector?’

‘You should be asking different questions. Like why was Krastev working at a medium secure unit? Was that by chance? Or was it where he could be close to someone? Someone he liked and admired maybe.’

Shaw’s gaze, fixed on Anna, was unflinching. She, in turn, searched his face for any sign of mischief, but found none. Shaw believed nothing happened coincidentally. It mirrored her own thinking. The answer to what took place next to the railway line lay across the waste ground in Ryegrove. Dawes pushed his chair back. Ready to go.

Shaw said, ‘Let’s let the sergeant go, Anna. I want a quiet word.’

Dawes immediately sat down again, but Anna said, ‘I’ll meet you in reception.’

Dawes threw her a quizzical glance. She returned it with a single nod.

When Dawes had gone, Shaw leaned forward and steepled his hands. ‘You’ve heard all that crap about parents. You know, how they should never have to bury their children? It’s a modern indulgence. Three hundred years ago you’d name all your children the same, knowing at least half of them would die.’

His tone caused Anna to frown. It wasn’t like Shaw to talk about his emotions. She waited for him to continue.

‘You lost your father early, right? I know it left a black hole. Losing Abbie left a bigger hole in me.’

‘Hector—’

Shaw held up his hands to stop her. ‘I’m not well. I’m bleeding from somewhere, the doc thinks. Probably bowel. I’m going to get tests. But the point is I’m going to ask you to promise me something. If you find out who was running Krastev, who the real sickness is behind all of this, you’ll tell me.’

‘You know I can’t give you information that’s part of an ongoing—’

Shaw did the same hand gesture and gave her a vulpine smile. ‘We both know that’s bullshit, Anna. It’s never bothered you before. I can give you more details of what Krastev said. But I need a promise. I need to know that if you find out who really killed my daughter, you’ll tell me, or you leave now, and I’ll bleed to death slowly not knowing. But you’ll have my blood on your conscience.’

Anna did not let her gaze drop because she knew it was what Shaw wanted.

‘Why?’ she said. ‘Why are you so desperate to know?’

‘Because if you tell me, I know the bastard will get what’s coming. I trust you to make the arsehole burn.’

It sounded plausible. She tried, for a moment, to put herself in Shaw’s place. Festering away in prison knowing her daughter’s killer was out there. Free to think about what he’d done. Free to plan. Free to do it again. It would have torn her apart.

‘OK. If I find anything, I’ll let you know.’

He sat back then, his whole body slumping as if talking to her had required a great effort.

‘When are the tests?’

‘A few days. They don’t tell me much. A scan, maybe stuff a camera up my colon. I’ll know when they give me the crap that makes you shit through a needle to clear everything out. But I’ll spend the time thinking about what Krastev told me and I’ll give it to you. That’s our deal, Anna.’

‘What will you do, email me?’

Shaw smiled. ‘You know we don’t have access to email, Anna.’

‘That’s never stopped you before.’

The smile widened. Anna had received several anonymous emails over a period of months. From the content, she had little doubt that the sender was Shaw, utilising his network of contacts within and outside the prison to get the messages to her.

‘I suggest we keep this all above board.’ Shaw looked at her under his hooded lids. ‘Come back to see me when you have something.’

She waited while they took him back to his cell, wondering what the doctors might find.

There was no death sentence in the UK. But perhaps, in Shaw’s case, nature was going to administer its own version.