It was a speeding ticket generated by one of the automatic cameras on the outskirts of the town. The date and time corresponded to Pieter de Groot’s murder. The photograph showed a black Volkswagen Golf with German plates. Like the one Margarethe Schilling’s partner had seen on her drive. Marijke felt her palms sweating as she read the details. The car was registered to Wilhelm Albert Mann. Twenty-six years old. His address was given as the Wilhelmina Rosen, care of a Hamburg shipping company. ‘Unbelievable,’ she breathed. It looked as if Tony had been right all along.

‘Does this help?’ Daan asked eagerly.

‘Oh yes,’ she said, amazed that she could still sound calm. ‘Yes, this helps a great deal. Thanks, Daan. Oh, and can you keep quiet about this for now? Confidentiality, and all that …’

He nodded. ‘No problem, Brigadier.’ He scuttled off, turning back at the door to give her a little wave.

The question was, what should she do now? Somehow, she had the feeling that the German detectives might be reluctant to see this as a high-priority solid lead. For one thing, it appeared to be nothing more than a combination of hunch and coincidence. There were plenty of innocent reasons why a German barge skipper’s car might have been in Leiden. There wasn’t even any proof that Mann himself had been driving it. More importantly, she understood only too well the politics of policing. No matter how eager the detectives were to clear their cases, there would be a reluctance on the part of their bosses to accept guidance from the Dutch police. They’d want the murders solved, sure, but they’d want the cases cracked by their own people. So while they might be glad of a lead on such a tough case, she didn’t think it would be treated with the urgency she thought it deserved. Besides, this had been her case from the beginning. If it hadn’t been for her and Petra, the German police would be a lot further behind than they were now. If anyone deserved the credit for solving these murders, it was them. She wasn’t ready to give it away yet.

What she needed was for one of her unofficial allies to track down the Wilhelmina Rosen and check out Wilhelm Albert Mann. If Tony was right about the killer’s boat being trapped by the floodwaters, it couldn’t be too hard to search the Köln area for Mann’s barge.

She walked back inside, mentally composing the e-mail.

Krasic looked down at the chubby young man who loomed over his keyboard like a miniature Jabba the Hutt. ‘What do you think? Can you find out about this Dr Anthony Hill for me?’