By nine thirty on Monday morning, the whole of the MCRTF were on the Ryegrove site. Anna dispatched Khosa and Holder to talk to Keaton and they’d now involved Terry Marshall, Ryegrove’s head of security. If Keaton was right, if what he’d found did lead to some sort of access way under the fence – and Anna had no doubt it would – they were going to need to get inside the hospital grounds and Marshall would need to establish a reasonable cordon. She was also sure he wasn’t looking forward to that. In the meantime, Anna and Dawes were ‘inside digging out’, as Dawes so aptly put it when he’d explained to the DCs why they needed to dress up warm while he and the boss would be nice and cosy with lots of NHS cups of tea to keep them perky.

Anna wasn’t sure about the tea, but the familiar conference room they’d adopted as a makeshift interview room was certainly warm. Monica Easterby met them at reception and ushered them through after the usual security checks. Someone had put silver flasks of hot water on a tray together with sachets of coffee and teabags and, much to Dawes’ delight, a whole plateful of digestive biscuits. Between enthusiastic munches, he sounded Anna out.

‘Is it me, ma’am, or do you think this is all a bit of a dog’s dinner?’

‘In what way?’

‘I’m just having a hard time linking a series of Internet-related deaths à la this bloody Black Squid, which is what brought us to the bodies in the first place, to this.’ Dawes waved a hand towards the walls and windows. ‘I mean, I can’t see anyone incarcerated here being capable of all that.’

Anna nodded. Dawes’ presence on the squad had come out of Rainsford’s hope that there might be a line of investigation that would help them understand the Black Squid deaths. That the information they were obtaining might uncover an existing threat to vulnerable kids. Digging about at the perimeter fence of a mental institution seemed a bit of stretch.

‘I know what you’re saying, Sergeant. But the fact is that Alison Johnson’s murder must fit into this picture somehow. We know that Jamie Carson’s “suicide” had the Black Squid’s ink all over it. Alison’s body is in the same place, she disappeared on the same date and now Keaton’s found something odd about the fence. She’s an inconvenience in this investigation but one that I think we need to pursue because I firmly believe it will throw up some answers to what was going on here. So, we keep at it.’

Dawes nodded, still sceptical but satisfied for now, it seemed, with what Anna had to say. He’d eaten two biscuits and drunk a cup of tea by the time the door opened and Easterby introduced Beth Farlow, dressed in the blue Ryegrove nursing uniform. Anna’s initial impression was of a slight, athletic girl with a combination of short dark hair, good skin and large eyes that made you want to look twice and then look back again.

Dawes said, ‘Cup of tea?’

Beth declined but Anna watched her relax. Tea meant she was being treated as a colleague here and Dawes knew it too.

‘Miss Farlow, are you happy for me to call you Beth?’ Anna asked.

‘I’d prefer it.’

The smile accompanying this little confirmation was bright and open. Anna couldn’t place the accent, except to know it wasn’t local.

‘OK. So, Beth, I’m not sure how much Mrs Easterby has told you, but we’re here to ask you specifically about Colin Norcott.’

Beth nodded. ‘That’s what she said.’ She looked suddenly troubled. ‘Is he all right? Has something happened?’

‘No. Not as far as we know. And what I’m about to tell you should remain confidential. We’re investigating a serious crime which may or may not involve this unit. How long have you been here, Beth?’

‘Four years. I qualified in 2013, did a year of non-forensic and then came here.’

Dawes nodded. ‘But you were involved in the treatment of Colin Norcott, we understand.’

‘Yes. I was part of the team handling his transition.’

‘You got to know him well?’

‘Yes, I’d say so.’

‘Good,’ Anna said. ‘Did he ever mention the name Alison Johnson to you?’

Beth frowned. ‘No. I know the name, of course, from what Mrs Easterby told me.’

Dawes said, ‘Then you’ll know she was a nurse who worked in this unit sixteen years ago. She went missing on 8 August 2001. We found her body buried near the railway line outside the hospital a week ago.’

Beth’s eyes widened in horror. ‘Do you think Colin—’

‘We’re trying to ascertain Alison’s movements on the night she disappeared,’ Anna said firmly. She needed Beth Farlow to be open. Accusing Norcott of anything at this stage might put the barriers up. She knew how fond some health professionals could get of their patients. Dawes took up the baton, his tone gentle but with just enough urgency to convey the seriousness of what they were about.

‘On the day, or rather the evening, Alison went missing, she was working, just like you are now. She had a connection with Norcott. You knew him well, I understand. Was he prone to agitation? Episodes of instability?’

Beth frowned, pondering the question. ‘Not really. But you have to remember he’d been here a long time. He could get anxious. Anyone who’s been in a place like this as long as Colin had would feel anxious about things.’

‘Such as?’

‘Moving back into the community, for example. He had anxiety over that.’

‘Nothing else? Was he frightened of anything specific? Birds, the colour blue, that sort of stuff?’

Beth smiled. ‘Are you asking me if he was mad, Sergeant? I get asked that a lot by people once they know I work here.’

‘The courts thought he was.’

‘Diminished responsibility can mean lots of things. He was here under a section 37. The court decided that he was mentally ill and needed the sort of treatment he wouldn’t get in prison. That applies to a lot of our patients. Colin had served his time and responded to therapy, and the tribunal thought he was ready to leave. But his anxieties were natural. The process of leaving here is a gradual one once a patient is deemed ready. We don’t simply open the doors and send them on their way. None of our patients would cope with that.’

‘And you know nothing about what happened between Norc— uh Colin and Alison Johnson the day she went missing?’

‘No, I didn’t say that. We knew about Alison. Of course, we did.’

‘What do you know?’

‘I know it was the day Colin stopped talking.’

Dawes had a notebook open on the desk. He stopped writing. ‘What?’

‘Didn’t you know?’ Beth looked genuinely puzzled. When neither of the detectives answered, she supplied the explanation. ‘It’s well documented in his notes. He was never very forthcoming apparently, but that day, the day Alison Johnson went missing, was the last day anyone heard Colin speak for years. Selective mutism is a known symptom in some cases of schizophrenia but that didn’t apply to Colin.’

‘So why did he do it?’

‘We never found out.’

‘How did you communicate?’

‘He wrote things down. Short sentences, words, nods. It’s no different from having someone with a speech impediment. And towards the end he got a lot better. He’d talk to me.’

‘Do you know why he stopped talking?’

Beth shrugged. ‘It’s tied up with anxiety disorders. But you’d better ask the consultants that.’

‘Pretend I’m a worried relative. Explain it to me.’

‘Colin was very traumatised by what happened. When he was convicted, I mean. He didn’t speak much when he first came here and that got worse after Alison Johnson went missing. He was improving when I first met him. But he made real progress in the eighteen months prior to his release.’

‘So, he did start to talk?’

‘A little. But he would still write things down more. On a pad. Basics, like shopping lists. Things he wanted to know. Answers when he wanted to give them.’

‘Did he respond to everyone or you alone?’

Beth shrugged. ‘You needed to gain his trust. Become one of his golems.’

‘Gollums?’ Dawes asked. ‘Like in The Hobbit?’

‘Golem,’ Beth said in a way that suggested it was an assumption she’d had to correct many times before. ‘It’s one of the ways Colin found to communicate. He made origami images of people he trusted. Once he did, you knew he’d let you in. He’d make them out of paper and write your name inside the head.’ Beth smiled. ‘It would be there when you unfolded it. He knew exactly where to write on a blank piece of paper so that it ended up hidden. Very skilful. As for communication, as I say mostly he’d write on a pad, but for important things, personal things, he’d write the question or the answer inside a golem.’

‘And this all started when Alison went missing?’ Dawes asked.

‘The golems, yes. That’s what I was told.’

Golems, thought Anna. Just like he was trying to do with Carys and Hywel Morgan. Change them into his dead father and his sister by ramming a message into their brains through their ears using a screwdriver. It surely didn’t take a degree in forensic psychiatry to work that out. Beth must have caught the look of distaste creeping over her face.

‘And yes, I do know what he did to his victims, but it was decided that his golems were an appropriate coping mechanism. Attempts were made through cognitive behaviour therapy to modify this compulsion, but it failed. He became very good at procuring materials. Toilet paper, tissues, envelopes. So, the team opted for moulding it into something positive.’

Anna nodded. ‘And you never felt threatened by him?’

Beth let out a tiny snort modified by a slow and deliberate shake of her head. It struck Anna as odd and exaggerated. As if her question had triggered a reflex response Beth found it necessary to embellish.

Is it so as not to let something show?

Beth said, ‘No, never. Colin… I know what he did was horrible but once we moved him from Somerton to Riverside, from medium to low security, he started to respond very quickly. I honestly don’t think he poses a risk to anyone and never did. Except for that one psychotic episode.’

‘The mushrooms?’ Anna asked

‘Colin’s mother has a lot to answer for.’

‘She was never charged.’

‘She claimed it was an accident.’

‘Did Colin ever mention her?’

‘Yes. He made golems of her. Inside he’d write the words, “I forgive you.” She was all the family Colin had left.’

‘Did she ever visit?’

‘Not in the time I knew him.’ Her face spoke volumes.

‘You didn’t like her?’ Dawes asked.

‘I know you must have read up on Colin’s file, so you must know what it was like for him after his father and sister were killed.’

Anna suspected Dawes had also read what she had about the deteriorating relationships between mother and son. But it would do no harm to be reminded of some of the detail. To that end, Dawes obliged.

‘Remind us,’ he said.

‘His mother blamed him for the accident and refused to talk to him afterwards. She refused to have him in the house. Made him sleep in a barn. Communication was through notes. To many people, myself included, it looked like she’d tried to poison him. The mushrooms were just a continuation of that persecution.’

‘I also read that Colin was computer savvy.’

‘Before he was admitted here Colin was very computer savvy. It was suggested that because of his isolation, the lines between reality and his virtual existence blurred. It was all taken away for many years. But he took to it very easily when it was reintroduced. Patients who are rehabilitated into the community have orientation in information technology. He’s bright.’

‘You sound almost fond of him,’ Anna said.

Something unreadable passed over Beth’s face. ‘It’s not unprofessional to feel sympathy for your patients,’ she said.

‘Do you keep in touch?’

‘It’s frowned upon. Someone in the community will now be supervising his care.’

They thanked her for her time. Anna gave her a card. ‘If anything occurs to you, anything at all, please give me a ring.’

‘I think about Colin, about what happened to him, a lot,’ she said as she left.

When she’d gone, Dawes got up and tested the water in the flasks. ‘Top-up?’ he asked. ‘Just about hot enough.’

Anna waited until the tea was brought before pressing Dawes. ‘Well?’

‘Norcott sounds complicated. But in my book, once a nutter always a nutter, under the right circumstances.’