It was important, he knew, not to let this profound disappointment erode his confidence in what he had already achieved. There was nothing in what Marijke had told him that undermined any of his previous conclusions. What he had to do now was to analyse the new material and incorporate it into his profile. This was simply an accumulation of more data, not an implicit criticism of his performance nor a marker of failure, he insisted to himself.

He could almost believe it, but not quite. He reread what had happened to Dr Calvet, his mouth tightening as his imagination conjured the scene before his eyes. This tiny, fragile woman, completely unsuspecting, an easy target for Geronimo. Odd, he thought. Most killers would have gone for such an easy target first. But this killer had so much confidence in his abilities that he’d started with much greater challenges. Tony wondered if having been disturbed in Bremen had shaken that confidence enough for him to have deliberately chosen a weaker victim in an attempt to shore up his belief in himself. ‘It must have been a shock to you, to have someone walk in on you in the middle of your moment of glory,’ he said softly. ‘You dealt with it, but it must be preying on your mind. Is that why you killed this one in her office? Did you think there was less chance of being disturbed there in the evening, after everyone had gone home?’

Whatever the answer to that question, the change of venue demonstrated that Geronimo was flexible in certain elements of his crimes. But the rape and the attempted strangulation weren’t markers of adaptability. They indicated something quite different. He pulled the laptop towards him and began to type.

Following the murder of Dr Calvet in Köln, he will be in a state of considerable agitation. The first three murders are apparently lacking in any obvious element of sexuality. However, there is invariably a link between serial homicide with ritualistic elements and erotic satisfaction for the killer. That there was no overt indicator of this in the earlier crimes would suggest to me that he was in denial about the sexual component in his actions. The rape of Dr Calvet should not, strictly speaking, be seen as an escalation in his activities. In practical terms, it represents the surfacing of a motivation that has been there from the beginning, albeit suppressed.