‘I think it’s a huge something. It ties in very neatly to a discovery I’ve just made in the Schloss Hochenstein records. Can you send me a list of places where I should be looking in Köln? I’m going to see if I can get on a flight and I’ll hire a car at the other end.’

‘OK, I will e-mail you the directions immediately.’

‘Don’t you think you should get your German colleagues on to this now?’ he asked.

‘I want to be more certain. And it’s still my case. If it wasn’t for me and Petra – and you, of course – there would be no leads to follow. I think we have the right to chase this ourselves. And I want to thank you for all you are doing for us,’ she said, her English competent but slightly stilted.

There was, Tony thought, little that was more powerful than naked self-interest. But he didn’t have a problem with that. In his experience of nailing serial killers, when it came to the endgame, it was always better to keep the team as tight as possible. ‘Listen, I haven’t felt so alive for ages. It’s me who should be thanking you. I’ll keep you posted.’

Within fifteen minutes, he was running out of the apartment, laptop swinging from his shoulder. He had forty minutes to get to the airport for a flight to Bonn. Luckily, he got a taxi almost immediately.

He was so excited it never occurred to him to check if he was being followed.

Carol couldn’t remember the last time she’d slept so long. She’d crawled into bed just before midnight, emotionally drained but still buzzing with excitement that she thought would keep her awake for hours. In spite of that, she’d crashed out as soon as her head hit the pillow, and when she’d opened her eyes it had been after ten.

As soon as she realized the clock hadn’t stopped the night before, she’d leapt out of bed and raced to the shower. She hadn’t written a single word of her reports from the previous day, and that was going to take hours. At this rate, Morgan and Gandle would be convinced she was either dead or fucking Radecki. She’d better send them a quick holding e-mail to warn them what was coming.

‘Bugger, bugger, bugger,’ she shouted as the water cascaded over her. She wanted to laze in bed, hugging last night’s encounter with Tony to her heart, replaying his every word. Instead, she was going to be stuck in front of a keyboard all afternoon, hammering out the details of her meetings with Radecki and Krasic.