Now, that future lay here in Bremen, a few miles away. His was a good cover story, he had to admit. He had worked long and hard on it. At first, he had thought of posing as a colleague, but realized that he would be too easily found out. Academics were always meeting at conferences and conventions; there was a high risk his victim might actually know the person he was pretending to be. And in these days of easy e-mail communication, it would be too easy to check. But what else would make them agree to a meeting?

Vanity, that was the key. They all loved to talk about themselves and their work. They were so sure of themselves, convinced they knew best about everything. But how to exploit that?

The answer had to lie in the new technology. It was easy to wear a mask there. They already had a computer on board, of course; so many of their consignments and movement orders arrived that way these days. He was intrigued by its potential for assisting him in his mission. So, he’d sent the boys back to Hamburg, laid the barge up for a week, bought a laptop computer and taken a crash course in the internet and website design. He’d registered the domain name of psychodialogue.com and created a website announcing the imminent arrival of PsychoDialogue, a new on-line magazine dedicated to the dissemination of current thinking in experimental psychology. He’d culled enough jargon from his own victim research to make it look like the real thing, he thought.

Then he had business cards printed up announcing himself as Hans Hochenstein, managing editor of PsychoDialogue. He had e-mailed his victims to arrange appointments to talk about their work, and the rest had fallen beautifully into place. One of the tutors on the computer course, a self-confessed former hacker, had even shown him how to send e-mails containing a logic bomb that would make them automatically erase themselves from the host computer after a predetermined period of time had elapsed. So even that potential fragment of evidence was gone.

Tonight, Dr Margarethe Schilling would pay for her cruelty and her vanity. He checked the directions she’d given him, savouring the irony of her willing contribution to her own downfall. Then he set off.