As she hurried down to the car, Marijke quietly cursed herself. She should have had the files searched before now. She’d had someone go through his personal papers, but because de Groot hadn’t been a practising therapist, it hadn’t occurred to her that his professional files would contain anything relevant to his murder. If this oversight proved anything, it was the value of sharing information.

She couldn’t help wishing she’d made the discovery herself. But at least she’d finally found something that might give Tony a unique insight into the killer’s mind. It was, she supposed, better than nothing.

Darko Krasic sat in the driver’s seat of his Mercedes, working his way steadily through a large bucket of salted and buttered popcorn and staring out through the rain at a small lake on the outskirts of Potsdam. The passenger door opened and a tall man folded himself into the seat, taking off a cloth cap and shaking the raindrops from it. He was neatly dressed in chinos and a windbreaker with the logo of a designer sportswear brand over the left breast. He had the lugubrious face of a man who is convinced the world holds only the prospect of disappointment. ‘Fucking awful weather,’ he said.

‘It’s always fucking awful weather in Potsdam,’ Krasic said. ‘The sun can be shining in Berlin, and down here, it’s grey and miserable. So, what have you got for me, Karl?’

KriPo detective Karl Hauser gave a sardonic smile. ‘So much for small talk, eh, Darko?’

‘Karl, we’re not friends. We’re never going to be friends. You’re on the payroll, that’s all. So what’s the point in pretending?’ Krasic lowered the window and tipped the remains of the popcorn on the ground. Even through the rain, the waterfowl spotted the bonanza and headed for the car.

‘Since you mention money, I think what I have for your boss is worth a bonus payment.’

‘You do, huh?’ Greedy bastard, Krasic thought. ‘Let me be the judge of that.’

‘That BMW bike? I’ve been doing some digging.’

‘That’s what us taxpayers pay you for.’

Karl scowled. ‘Listen, Darko, what I’ve been doing for you goes way beyond the call of duty. Katerina Basler’s death was written off as an unfortunate accident. We’ve got more important stuff than that to deal with.’

‘OK, OK, Karl, we appreciate what you’re doing. And you know you’ve always been well rewarded in the past. So, you’ve been doing some digging …?’