Marijke frowned at the notes she’d made. Hartmut Karpf, the detective from Köln, had decided to call her directly as well as sending his initial notes via Europol because there were discrepancies between their two cases that he wanted to discuss. ‘I’ve spoken to my colleagues in Heidelberg and Bremen, and it’s not that I doubt we’re dealing with the same man,’ he’d said. ‘But I thought you should know that I think we’re looking at a serious escalation here.’

‘I appreciate you calling,’ she’d said. ‘So, what exactly do you have?’

‘You want the whole story?’

‘Everything you have, from the beginning.’

The rustle of paper down the phone, then he spoke. ‘OK. Dr Marie-Thérèse Calvet, aged forty-six. Senior lecturer in experimental psychology at the University of Köln. She didn’t turn up for work this morning, and her secretary couldn’t get a reply from her home number. She was due to give a seminar, so one of her colleagues was enlisted to stand in for her. But the slides that accompanied the seminar were locked in Dr Calvet’s office. So the colleague borrowed the master key from the janitor and let himself into her office. Dr Calvet was lying naked and dead, tied to her desk.’ Karpf cleared his throat. ‘Her colleague was not exactly helpful. He threw up all over the crime scene.’

‘If it’s any consolation to you, it probably made no difference. This killer doesn’t leave us anything to work with in forensic terms,’ Marijke said consolingly.

‘I gathered as much. Our scene-of-crime officers were very disgruntled. Anyway, for the record, Dr Calvet’s body was on its back, arms and legs spread out, each tied to a leg of the desk near the floor. Four standard reef knots, incidentally. Her clothes were underneath her, they’d been cut away once she was tied down. And it was obvious that her pubic hair had been cut away, along with the skin.’

‘So far, this is all according to his pattern,’ Marijke said.

‘Except of course that this is the first time he has killed someone inside their university,’ Karpf corrected her. ‘All the other victims were found in their homes.’

‘That’s true,’ Marijke said, mentally kicking herself for her stupidity. But at least now she knew she was dealing with a detective who was as sharp as this inquiry needed. ‘What else did you find?’

‘I demanded an urgent postmortem. Dr Calvet sustained two blunt trauma head wounds, at least one of which would have been enough to knock her out for a while. There were bruises to her throat consistent with manual strangulation.’

‘That’s new,’ Marijke confirmed.