Fabel looked again at the place that just under a year ago had been a murder crime scene. It was a narrow alley between two four-storey apartment buildings. It was cobbled and swept clean. A row of recycling and waste bins lined one side, allowing room for only one person to pass. The bins had been there at the time of the murder. Fabel had seen the scene-of-crime pictures. Being there in person confirmed the instinct he had had when looking at the photographs.

‘It has always been assumed that the killer followed the victims. Picked them out from the Karneval crowds because of their physical forms fitting his agenda. But I think the selection has been made long before that. Weeks. Maybe months. Maybe he was on their trails during the evening, but my reckoning is that he knew exactly where they lived and overtook them or predicted their movements. I think he was waiting here for Melissa Schenker when she came home. In the dark, in this confined space, like a trapdoor spider.’

‘So he selected the locus well in advance? Not just the victim?’

‘Yep … and that makes him a whole different proposition,’ said Fabel. ‘Serial killers come in two types: the impulsive and the organised. The impulsive types simply respond to their appetites. They scratch when they itch. Cannibalistic serial killers tend always to be impulsive and that is what I thought we were perhaps dealing with here.’

‘Does it make that much of a difference?’ Kris Feilke’s acne stood out even more vividly against the blue-white of his chilled skin.

‘Yes, it does,’ said Fabel. ‘Both types commit a series of murders, both often take trophies, both have borderline personality disorders, both tend to be loser types … but there is a huge difference between them. Impulsive serial killers have below average IQs. Often significantly below.’

‘Like Joachim Kroll …’ Scholz referred back to their discussion in the restaurant.

‘Like Joachim Kroll. But organised serial killers usually have IQs way above average. And they know it. They are smart, but they’re never quite as smart as they think they are. Anyway, I’m beginning to think that our Karneval Killer is an organised type. A planner. Especially in this case. Melissa Schenker was an almost total recluse. That was something else that I noticed in the files you sent me. Schenker had practically no social life other than the two friends who were always trying to draw her out of her shell.’

‘That’s right. They were the ones who persuaded her to come out with them on Weiberfastnacht. Poor girls. I interviewed them. They were completely distraught and riddled with guilt. They felt that if they hadn’t cajoled Melissa to come out she would still be alive.’

‘They’re probably right. But what I don’t get is the selection of Melissa. Our killer is a tracker and hunter. He must have seen her somewhere outside her apartment.’