Despite it being nearly noon and despite the absence of all but the occasional shard of glass in the windows that ran the length of one wall, the swimming pool had a gloom to it, as if the grime from the walls and floor had pervaded the air and dulled the light. Now the filth of the swimming pool was accentuated by the stark arc lights that the Tatort forensic team had set up. There were used syringes, condoms, litter and, in one corner, what looked like human excrement. Fabel couldn’t imagine a seedier place to die.

A six-strong Tatort team, clad in white forensic overalls, were sifting through the filth. Brauner, the head of the team, squatted down beside the body. Klugmann’s hands had been tied behind his back and a sack placed over his head. Brauner had carefully cut away the sacking, which had half stiffened with blood that had caked and dried. He looked up and nodded when he realised Fabel was behind him, standing at the pool edge.

‘He was shot while kneeling where you are,’ said Brauner. ‘Execution style and straight through the brain stem. A really professional job. He would have been dead before he hit the bottom. The bullet exited above the mouth.’

‘How long has he been dead?’

‘You’ll have to ask Möller when he examines the body, but from the temperature, the post-mortem lividity and the easing of rigor, I’d say at least a couple of days. Maybe three.’

One of the team called out from the corner of the pool. ‘Herr Brauner. Over here!’

Fabel followed Brauner up to where the forensic technican had called.

‘Here …’ The technician pointed to a small metal cylinder that glittered among the dust and debris on the floor. Brauner squatted down on his heels and carefully picked up the object.

‘A nine-millimetre cartridge.’ Brauner carefully picked up the casing between latex sheathed thumb and forefinger.

‘And lying in clear sight of the shooter,’ said Fabel. ‘A piece of evidence he could easily have denied us just by casting a quick eye around him. An amateurish mistake for such a professional killer to make.’

Brauner shrugged. ‘Maybe it was dark. Or maybe he thought he was about to be discovered and made a quicker exit than he’d planned.’

‘Could be …’ Fabel was far from convinced. He could see from the creases on Brauner’s brow that something was troubling him. ‘What is it?’

‘This cartridge is a nine-millimetre all right, but it’s not from a common automatic. What is it you carry? A SIG-Sauer P6?’

‘A Walther P99.’

‘This wouldn’t fit either. Most nine-mils are based on either the Smith and Wesson or the Walther configurations. I suspect this is a nine-by-nine-by-seventeen. It’s non-standard ammo for a non-standard firearm.’

‘Any idea what?’

‘Not at this stage. We’ll be able to narrow it down to a few makes, but it’ll take time.’

Möller, the pathologist, arrived. Fabel nodded an acknowledgement.

‘He’s been dead a couple of days,’ Fabel told Möller as he made his way to the door out of the pool. He smiled at Möller’s indignation and made his way out into the fresh air. Volker was half leaning, half sitting on the wing of one of the green and white Schutzpolizei cars.