‘About three and a half years ago, Garvey had what looked like an epileptic fit in his cell at Whitemoor, gashed his head open on the side of his bunk. Turns out he’d had a few similar episodes, so they took him to the district hospital in Peterborough and did a CT scan. They would only have had the vaguest idea of what they were looking at, but we’re image-linked to most of the other hospitals, so they were able to ask us to have a look. We had… more than a vague idea. He came here a few weeks later for an MRI.’

Kambar stood up and took the plastic brain from the shelf. ‘He had a massive tumour at the base of the frontal lobe. What’s called a benign meningioma.’

‘Benign?’ Holland said. ‘I thought it was the malignant ones that killed you.’

Kambar was turning the plastic brain over in his hands. ‘They’ll kill you slightly quicker, that’s all. If a benign tumour grows big enough, the inter-cranial pressure will almost certainly be fatal. That’s why we needed to operate. Here…’ He lifted the model with one hand and pointed with the other to a pair of narrow parallel strips at the back. ‘These are the olfactory grooves.’

‘That’s smell, right?’ Holland asked.

Kambar nodded. ‘Garvey’s tumour was sitting right there. A whopping great olfactory-groove meningioma.’ He looked at Holland. ‘In fact, issues with the patient’s sense of smell are often among the earliest symptoms. Garvey claimed he had been having problems for many years. Smelling burning or petrol for no reason. Smelling nothing at all, more often than not. Sadly for him, his tumour did not present fully until long after these problems began, by which time it was far too late.’

Thorne took the model from Kambar and held it for a few seconds until he started to feel a little foolish, then passed it over for Holland to put back on the shelf. ‘So, you operated?’

‘Not for several months,’ Kambar said. ‘The inter-cranial pressure was building, no question, but there was no reason to think he was in any immediate danger. Anyway, it took him a few weeks to make up his mind. It was a high-risk procedure.’

‘But he still decided to go ahead.’

‘He did a good deal of hard thinking,’ Kambar said. ‘Took advice from some of the people he was close to. Not that there were lots of them, of course.’

‘Not too many likely to miss him,’ Holland said.

‘Quite.’

‘So he died on the table?’ Thorne asked.

‘Shortly afterwards,’ Kambar said. ‘An extradural haemorrhage. He never really woke up.’ He switched off the light box, took down the X-ray and handed it to Thorne. ‘You can keep this, if it will be useful.’

Thorne looked at the three pictures of Raymond Garvey’s brain, the tumour that had grown within it. Garvey had brutally murdered seven women and, though it had happened earlier than he might have liked, he had been granted a relatively peaceful death. Now, three years on, someone was killing again. But why? On his behalf? In his name? Someone had left pieces of this very picture for the police to find and they still had no idea how it had come to be in his possession, nor what connected him to Raymond Garvey.

‘Any idea who he might have spoken to?’ Thorne asked. ‘Those people you said he was close to.’

Kambar thought for a few moments, chewed the end of his pencil. ‘There were a couple of other prisoners, I think. Other vulnerable ones, like him.’

‘I don’t suppose you can you remember any names?’

‘I’m sorry.’

Thorne turned to Holland. ‘Maybe we should get over to Whitemoor this afternoon.’

Holland smiled. ‘You angling for another overnight?’

‘And the son, obviously,’ Kambar said.

‘We’ll make it back tonight-’ Thorne stopped. He watched Holland ’s eyes go to Kambar, saw the confusion on his face, then spun around in his chair. ‘Sorry, what?’

‘Yes, thinking about it, his son probably ended up with all Garvey’s things,’ Kambar said. ‘The X-rays and so on, after the funeral.’

‘Garvey had no relatives,’ Thorne said. ‘Well, there’s an elderly uncle somewhere, but certainly no son.’

Kambar pulled a face, as if he were struggling with a particularly cryptic crossword clue. ‘Well, there was definitely someone claiming to be his son. Someone who made my life rather a misery for a number of weeks after Garvey died. Leaving all sorts of messages, ranting on my answering machine. I’m pretty sure the same went for the governor at Whitemoor. Pestered the poor chap for ages.’

‘What was his name?’

‘Anthony Garvey.’

‘“Anthony” was Ray Garvey’s middle name,’ Thorne said. ‘Sounds iffy to me.’ He sat back, shaking his head. ‘No… can’t be.’ He looked at Holland, who could do no more than throw up his hands.

‘Well, Garvey thought he was his son,’ Kambar said. ‘This man visited him several times a week for years. He had hundreds of letters from Garvey, too.’

‘What do you mean he made your life a misery?’ Holland asked. ‘Did he blame you for what happened to his father?’

‘Not so much that,’ Kambar said. ‘Although he obviously wasn’t happy about the consequences of the operation. No, he thought there should be a retrial-’

Thorne sat up very straight. ‘What?’

‘He wanted me to give evidence on his father’s behalf.’

‘Why on earth would there be a retrial? There was never the slightest doubt that Garvey was guilty.’

‘Never the slightest doubt that he committed the murders, certainly. ’

‘I’m not with you.’

‘Anthony Garvey was convinced that, were there to be a retrial, his father’s conviction would be overturned. They had been talking about it ever since Garvey was first diagnosed.’ He jabbed the tip of his pencil at the X-ray in Thorne’s lap. ‘They were convinced that the tumour had altered his personality; that effectively he had not been himself when he had killed those women. He wanted me to clear his father’s name.’

Thorne looked again at Holland, who was scribbling furiously. He glanced up, shrugged and returned to his notebook. Thorne turned back to Kambar, but could not think of anything to say. The information was still settling, the different strands becoming tangled as quickly as he tried to tease them out.

‘You still haven’t said what this is all about,’ Kambar said. ‘Raymond Garvey has been dead for over three years.’

Holland stopped writing. ‘I’m sure you understand that we’re not really at liberty to go into details.’

‘Of course.’ Kambar looked a little embarrassed, began to straighten some papers. ‘Just curious, that’s all. It would be nice to know what was going on.’

‘You’re at the back of a very long queue,’ Thorne said.

The Addenbrooke’s staff canteen was no more pleasant a place to eat lunch than its equivalent at Becke House. The food was probably a little better, as was the standard of conversation at the tables, but even on the top floor, which was dedicated to administration, there was no escaping that hospital smell.

Bleach and whatever else.

They carried their trays to a table in the corner, put down plates and cutlery, a bottle of still water and a can of Diet Coke. Both had plumped for the lasagne, though the doctor had chosen to accompany it with a green salad, which had almost, but not quite, prompted his visitor to put back his chips.

‘What will your colleague do for lunch?’ Kambar asked.

‘Not sure,’ Thorne said. They had rung through to make an emergency appointment with the governor at Whitemoor and, once it was confirmed, Holland had taken a cab back to Cambridge station. From there, it was a thirty-minute train journey to the small station at March, which was a short taxi ride from the prison.

‘He might get there in time to eat with the governor.’

‘Maybe,’ Thorne said. He guessed that Holland would prefer to make other arrangements. As far as smells that stayed with you long after you’d left the premises went, there wasn’t much to choose between a hospital and a prison. ‘He’ll probably just grab a sandwich on the train.’