‘I’ll take that as a yes.’ She got to her feet and retrieved the remains of her breakfast. She had just made it as far as her own desk when Hoofdinspecteur Kees Maartens barrelled through the squad-room door, his meaty hand dwarfing the can of Coke that was halfway to his mouth. He took a swig as he strode, tossing the empty can into the next wastepaper bin he passed. Recycling was for people with time on their hands, not for busy men like him, his gesture seemed to say.

‘What’s new?’ he demanded, stopping beside Tom’s desk.

‘Nothing of any significance,’ Tom said.

Maartens turned towards Marijke. ‘What about you, Marijke? Anything useful come through from forensics yet?’

She shook her head. ‘It’s all negatives. Nothing that takes us any further forward.’

Maartens rubbed a hand along his jaw. ‘I hate this case,’ he muttered. ‘It makes us look stupid.’

‘Marijke’s got a good idea,’ Tom volunteered.

Gee, thanks, she thought as Maartens turned back to her, his heavy brows lowering in an interrogative frown. ‘What’s that, Marijke?’ he asked.

‘I’ve been thinking about how meticulous de Groot’s killer was. How methodical, how organized. This wasn’t a spur of the moment thing. It was planned. What it reminds me of is the work of a serial killer. I know we’re all worried about the prospect of him killing again if we can’t catch him, but it occurred to me that he might have killed before.’

Maartens nodded, his head to one side. He crossed to her desk and dropped into a chair facing her. ‘I can’t argue with the theory,’ he said heavily. ‘But haven’t we already checked to see if there’s anything similar in the records?’

‘We can only check Dutch records, though,’ Marijke said. ‘What if his previous victims weren’t in Holland? What if he’s killed in Belgium or Germany or Luxembourg? We’d have no way of knowing.’

‘And these days, post-Schengen, we’re all citizens of Europe,’ Maartens said acidly. ‘I see what you mean, Marijke. But how does that take us any further forward?’

‘Well, I’ve noticed in the past few months that the bulletins coming out of Den Haag from Europol have been a lot more specific. They used to be fairly generic, but now they’ve taken to circulating much more detailed requests for information about particular areas of concern. I wondered if it might be worth approaching them and asking them to include a request for information about any similar cases elsewhere in the EU?’

Maartens looked deeply sceptical. ‘Don’t you think it’s a bit too near street level for them? They’re only interested in the stuff that lets them play with their fancy computer databases. They don’t want to get their hands dirty with something as vulgar as murder.’