‘And you’re here because of Joseph Lintz?’

‘I’m here because DI Abernethy says you’re determined to link the murder of Joseph Lintz with the various accusations which have been made against him.’

‘And?’

‘And that, of course, is your prerogative. But there are matters not necessarily germane which might prove ... embarrassing, if brought into the open.’

‘Such as that Lintz really was Linzstek, and was brought to this country by the Rat Line, probably with help from the Vatican?’

‘As to whether Lintz and Linzstek were the same man ... I can’t tell you. A lot of the documentation was destroyed just after the war.’

‘But “Joseph Lintz” was brought to this country by the Allies?’

‘Yes.’

‘And why did we do that?’

‘Lintz was useful to this country, Inspector.’

Rebus poured a fresh whisky for Abernethy. Harris hadn’t touched his. ‘How useful?’

‘He was a reputable academic. As such he was invited to attend conferences and give guest lectures all round the world. During this time, he did some work for us. Translation, intelligence-gathering, recruitment ...’

‘He recruited people in other countries?’

Rebus stared at Harris. ‘He was a spy?’

‘He did some dangerous and ... influential work for this country.’

‘And got his reward: the house in Heriot Row?’

‘He earned every penny in the early days.’

Harris’s tone told Rebus something. ‘What happened?’

‘He became ... unreliable.’

Harris lifted the glass to his nose, sniffed it, but put it down again untouched.

‘Drink it before it evaporates,’ Abernethy chided. Harris looked at him, and the Londoner mumbled an apology.

‘Define “unreliable”,’ Rebus said, pushing aside his own glass.

‘He began to ... fantasise.’

‘He thought a colleague at the university had been in the Rat Line?’

Harris was nodding. ‘He became obsessed with the Rat Line, began to imagine that everyone around him had been involved in it, that we were all culpable. Paranoia, Inspector. It affected his work and eventually we had to let him go. This was years back. He hasn’t worked for us since.’

‘So why the interest? What does it matter if any of this comes out?’

Harris sighed. ‘You’re right, of course. The problem is not the Rat Line per se, or the notion of Vatican involvement or any of the other conspiracy theories.’

‘Then what is ...?’

Rebus broke off, realised the truth. ‘The problem is the personnel,’ he stated. ‘The other people brought in by the Rat Line.’

He nodded to himself. ‘Who are we talking about? Who might be implicated?’

‘Senior figures,’ Harris admitted. He’d stopped playing with the glass. His hands were flat on the table. He was telling Rebus: this is serious.

‘Past or present?’

‘Past ... plus people whose children have gone on to achieve positions of power.’

‘MPs? Government ministers? Judges?’

Harris was shaking his head. ‘I can’t tell you, Inspector. I haven’t been trusted with that knowledge myself.’

‘But you could hazard a guess.’

‘I don’t deal in guesswork.’

He looked at Rebus. There was steel behind the eyes. ‘I deal in known quantities. It’s a good maxim - one you should try.’