Alex leaned back in his chair, on full alert. He was in his office with the door firmly closed. A new routine that had been established over the past few days: he and Fredrika worked behind closed doors, together or separately.

Creeping around. Just like Berlin said. I hate it.

‘I’ve got a thousand other things on my plate,’ Alex said. ‘But if I can help you, fire away.’

Renata was an important person in Alex’s professional life. He tried to remember that, give her the time she needed.

‘Thank you. So as I said, we’re looking at an elderly male. Divorced, lived alone in central Stockholm. The neighbours became aware of an unpleasant smell, and eventually tracked it down to his apartment. I’d say he’d been dead for four to six days by the time he was found.’

Alex grimaced, wondering where the conversation was going.

‘It wasn’t difficult to work out the cause of death,’ Renata went on. ‘Not once I knew what I was looking for. There were contusions on his throat suggesting a violent attack, but I didn’t think that had killed him. He’d had heart problems for some time, and I was afraid that the blow to his throat had led to a heart attack.’

She paused for breath. Alex was surprised; Renata was usually much more concise.

‘But it wasn’t his heart either,’ he said.

‘No. When I turned him over I discovered a puncture wound in the nape of his neck.’

Alex opened up his computer. ‘Okay,’ he said, mainly to indicate that he was listening.

‘Someone had given him an injection,’ Renata clarified.

‘Strange place to choose,’ Alex said as he skimmed the newspaper headlines. The journalists weren’t holding back, but he couldn’t blame them; an unusual amount of blood had flowed in Stockholm over the past few days.

And I have no idea how to stop it.

‘Very strange,’ Renata said. ‘So strange that I immediately regarded it as a deviation. Almost ritualistic.’

Ritualistic?

‘Was there any kind of message on the victim?’ Alex asked.

‘Message?’

‘A piece of paper – a book, maybe?’

The brief pause told him that Renata was taken aback.

‘No. No message, no book.’

Alex thought for a moment. If there had been a message, the officers on the scene would have noticed it. Or would they? Berlin had imposed a complete lockdown on the inquiry; anyone not directly involved in the investigation wouldn’t be aware of the killer’s MO.

I need to check that. Alex made a note.

‘Anyway,’ Renata continued, sounding more than a little irritated by the interruption, ‘the injection into the back of the neck doesn’t remind you of anything?’

‘No.’

‘Not even if I tell you that the man who died had significantly elevated insulin levels?’