‘It looks that way,’ said Kessen. ‘Europol intelligence has come up with two more associates of Nikolov’s: the Zhivko brothers – Anton and Lazar. It appears they were members of a criminal gang that got involved in some kind of turf war. The older brother, Anton, was badly injured. He got a bullet lodged in his spine and was left paralysed from the waist down. The Zhivkos had enough money stashed away from their criminal activities that they were able to do a runner and get clear of the country.’

‘Don’t tell me they’re here?’

‘Yes, right here in Derbyshire. Two years ago, the Zhivko brothers opened an electrical shop in Chesterfield. It’s possible Nikolov came here to join them. So far, they’ve behaved themselves, but Europol have passed on a tip-off that the Zhivkos are expecting a visitor from their own country – a visitor they might not welcome. An organized crime surveillance unit has been set up in Chesterfield to keep an eye on things.’

‘An East European feud happening on our territory?’ Hitchens ran a hand through his hair. He was starting to look less elegant than he had when the week started. ‘We’d better find out if we have any more Bulgarians in the area. I’ll run a check on the dispersal facilities, for a start.’

Kessen studied Fry. ‘There’s a job for you, Diane. Europol have arranged for an English-speaking officer to liaise with us from Pleven. He’ll be calling this morning. And I want you to deal with him.’

Fry was aghast. ‘With respect, sir, I’ve got far more important things to do than become involved in international liaison – especially on the basis of such a tenuous connection.’

‘Not quite so tenuous,’ said Kessen calmly. ‘DC Cooper is following up a potential lead to Simon Nichols in the exact area where Rose Shepherd made calls to a public phone box. And don’t forget that the victim had the international dialling code for Bulgaria in her address book – the magic 359.’

Still fuming, Fry went back to her own desk. Bulgaria. The Balkans, right? A former Soviet bloc country, a bastion of Communism during the Cold War era. But what else did she know about it? Nothing.

Fry was still trying to picture what a Bulgarian might actually look like, when her phone rang.

‘Hello, DS Fry.’

‘Alo. My name is Sergeant Georgi Kotsev. I’m calling from Pleven Police Department, on behalf of the Bulgarian Ministry of the Interior.’

Fry tried to mask her sigh. ‘Oh, Sergeant Kotsev. Hello. Thank you for sparing the time to talk to us.’

‘It’s a pleasure to co-operate with our colleagues in the United Kingdom.’