Karolina nodded. ‘He wanted to watch me have sex with someone else. That’s when I said no. He was angry with me, of course, and told me I was ruining his rehab programme. But that was my line in the sand.’

‘And then what happened?’

‘Nothing, really.’ Karolina shrugged. ‘In the end, I accepted that he just couldn’t do it. I should of course have left him there and then, but instead, we decided to try to have a baby through insemination. Don’t ask me why, but at the time it felt like a solution to our problems.’

‘And when was this?’

‘2001. Rutger was born a year later.’

That was the same year Jacobsén had quit his permanent job to start his own business. Was it Karolina’s refusal to let him watch her that had triggered his decision? Was that what had made him start installing hidden webcams?

It sounded improbable. But for Jacobsén, with his background in the security industry and knowledge about the latest surveillance technology, it was definitely possible.

What he hadn’t found was any logical connection to Columbus. What had made him go from watching to doing? ‘So in all the years you’ve been together, you’ve never had sex?’