‘Did she ask you to ask me that question?’

‘It doesn’t work like that, Dan. This isn’t an interrogation. It’s an assessment.’

Shepherd took a deep breath, forcing himself to relax. Stockmann wasn’t the enemy, but the question had caught him off guard.

‘So why would you ask me a question like that?’

‘Because of the nature of your career. You were a soldier, you were in the SAS, you moved to the police, then the Serious Organised Crime Agency, and now you’re with MI5. I was wondering if during the course of those different jobs you’d ever been asked to take a life in a situation where combat wasn’t involved.’

‘Because?’

‘Because I’d be interested to know how you reacted. Whether guilt kicked in afterwards.’

Shepherd nodded slowly. He didn’t like lying to the psychologist, but she had given him no choice. Yes, he had been in situations where there had been no combat, where he’d helped to cold-bloodedly take the lives of men who were no immediate threat. And no, there had been no guilt afterwards. But he couldn’t tell Caroline Stockmann. He shrugged carelessly. ‘It’s never happened,’ he said.

‘That’s a relief,’ she said. ‘From your point of view, I mean. It’s not something I’d want to put to the test.’

‘What about you, Caroline? Do you think you could take a life?’

She laughed carelessly. ‘Me? Good gracious, of course not,’ she said. ‘How on earth could I? I don’t have the strength, mental or physical. I’m one of life’s victims.’

‘That you’re not,’ said Shepherd. ‘But say you were at home and a rapist broke in and you had a knife.’

‘That’s a lot of ifs.’

‘It’s only two,’ said Shepherd. ‘Rapist. Knife. Do you stab him to save your life?’

‘I suppose so, yes.’

‘And suppose someone was about to kill your husband or wife. Would you kill them?’

‘Yes,’ she said, more confidently this time.

‘See, you do have what it takes,’ said Shepherd.

‘If pushed, anyone can kill, is that what you’re saying?’

Shepherd nodded. ‘And if you were defending your child, I don’t think there would be any guilt. Do you?’

‘I suppose not.’

‘Now let’s take it a step further. Suppose someone murdered your child. And you knew without a shadow of a doubt who’d done it. Would you kill them if you could?’

‘That’s too hypothetical, Dan.’

‘How can anything be too hypothetical? It’s a simple question.’

‘But not one that I can answer in the abstract. We can’t take the law into our own hands.’

‘You think the criminal justice system is working, do you?’

‘You’re very good at that, aren’t you?’ she said.

‘Good at what?’

‘At deflecting questions by changing the subject. You do it so subtly that one’s hardly aware of you doing it.’

Shepherd chuckled. ‘It’s a necessary skill when you’re undercover,’ he said. He put up his hands. ‘Sorry, go ahead. Ask away.’