He hadn’t taken to Kurt, he recalled. He’d made not a virtue but a martyrdom of necessity, complaining about his boring life of childcare following his redundancy from a research post with a pharmaceutical company. ‘Of course, having to look after a child all day means it’s impossible for me to keep my knowledge current,’ he’d moaned over dinner. ‘It’s all right for Margarethe, she can scale the heights of the academic world, but I’m stuck out here in the backwoods with my brain rotting.’

It had become clear to Tony that Kurt was parenting not out of necessity but out of idleness. According to Margarethe, his parents had left them enough money to buy the house with a little left over. Kurt had seized the chance to take redundancy with the intention of assuming the life of a dilettante. As she told the tale, Margarethe had smiled wickedly. ‘The first thing I did when he told me what he’d done was to sack the nanny. He couldn’t argue with me, because it would be like saying he didn’t want to spend time with his son. But he’s never forgiven me for it.’

At the time, Tony had thought it was remarkably bad psychology for someone who made her living out of the labyrinth of the human mind. Unless, of course, she had wanted the marriage to fail. Which had followed with depressing inevitability, as he’d gathered from her Christmas cards and occasional e-mails. What she hadn’t expected was for Kurt to hang on to Hartmut, and he could tell, reading between the lines, that the loss of her son had devastated Margarethe.

And now, if this report was to be believed, Margarethe’s son had lost her in the most final of ways. Tony still couldn’t take it in. There was a terrible element of happenstance in such a death.

It was too late for Margarethe. But it might not be too late for others. Never mind that it suited him to escape the press baying for comments on Jacko Vance. Never mind that he was desperate with boredom in his job. And never mind that he wanted to be near Carol. Saving lives was paramount.

For better or worse, he’d made his choice.

In the half-hour before she could expect to find Marijke in the chat room, Petra browsed the web, dipping in and out of various serial killer sites to see if she could find any correspondences between recorded cases and the particular fetishes of their own killer. But her search proved fruitless. The depraved minds whose activities were recorded in lurid detail hadn’t indulged in death by this sort of drowning, nor could she find cases of pubic scalping, though she did discover that it had a name – gynelophism. Not much help there when it came to attempting to extract some motivation for their killer.