‘I don’t give myself as much to philosophical musings as you do,’ he lied, with a smile.

‘I always thought of myself as too impulsive. Chaotic. Maria was always so disciplined and organised. Having said that …’ Anna indicated the CD collection. ‘This is bordering on the anally retentive. Look at these CDs … all ordered by genre and then alphabetically. Life’s too short …’

Fabel laughed, mainly to disguise the unease he felt at seeing how similar Maria’s taste and way of living were to his. They went through to the flat, checking each room. Fabel found what he was looking for, but had hoped not to find, in the smallest of the three bedrooms.

‘Shit …’ Anna gave a low whistle. ‘This is not good. Not good at all. This is obsessive.’

‘Anna …’

‘I mean, this is the kind of thing we’ve come across with serials …’

‘Anna – that’s not helping.’

Fabel took in the small room. The walls were covered with photographs, press cuttings and a map of Europe with location pins and notes attached. There wasn’t a square centimetre of clear wall space. But this was no chaos. Fabel could see four defined areas of research: one related to Ukraine, one to Vitrenko’s personal history, one to people smuggling, one to organised crime in Cologne.

‘Maria hasn’t been spending her time recuperating,’ said Anna. ‘She’s been working. On her own.’

‘You’re wrong. This isn’t work. This is vendetta. Maria’s planning her revenge on Vitrenko.’

Anna turned to Fabel. ‘What do we do, Chef?’

‘You take the desk. I’ll go through the filing cabinet. And Anna … this stays between us. Okay?’

‘You’re the boss.’

Fabel and Anna spent two hours going through Maria’s files and notes. They were full of contacts with whom she had spoken, probably using her position as a Polizei Hamburg officer to gain access to otherwise confidential information: the Anti-Trafficking Centre in Belgrade, Human Rights Watch, a people-smuggling expert at Interpol. There were notes on all aspects of current people-trafficking in Europe, a full dossier on Ukrainian Spetsnaz units and a file of even more cuttings that hadn’t made it to the wall display. Among them were articles about a fire in a container truck in which several illegal immigrants heading for the West had been burned to death; about a model in Berlin who had been murdered with acid; about a bloody underworld feud in the former Soviet Republic of Georgia; about a Ukrainian-Jewish crime Godfather who had been found murdered in his luxury apartment in Israel.

‘What have you got?’ he asked Anna.

‘A list of hotels in Cologne. Nothing to say which one she’s going to use, but I’d say it was a short-list. She’s been corresponding with someone in the Interior Ministry of Ukraine. Sasha Andruzky.’