An incident room had been opened up in Edendale for the Rose Shepherd enquiry. A fatal shooting was still rare enough in Derbyshire to make Miss Shepherd’s murder a high-profile case, even if she hadn’t been a respectable middle-class woman gunned down in her own home.

Watching the staff arriving at E Division headquarters, Cooper deduced that the HOLMES system was being activated. He recognized an allocator he’d worked with on a previous enquiry. The others would be data inputters, a receiver, an analyst.

With no obvious lines of enquiry that might lead to a quick conclusion, the HOLMES computer indexes would be vital in sniffing out correlations as information came in. One tiny detail could send the investigation in a new direction.

Before the morning briefing started, Cooper joined a small crowd examining the display of crime-scene photographs from Bain House and the field behind it. Some of the interior shots showed the victim from different angles before her body was removed to the mortuary. On the lower part of her torso, where it was in contact with the floor, there was a large, bruise-like discoloration that he hadn’t noticed before. That was dependent lividity – the effect of gravity on blood that was no longer being pumped through the veins. At least it showed that no one had moved the victim after she was killed.

‘The victim was killed with a semi-automatic weapon, at least three shots fired in rapid succession,’ said DI Hitchens, opening the briefing. ‘We know it wasn’t a bolt-action rifle. Since even one of the shots would have put her down on the floor, the second shot has to have followed rapidly to strike the victim before she fell. Otherwise, she’d have been out of sight below the window sill, with no chance of a second shot hitting its target.’

Officers around the room began to call out questions, their voices difficult to distinguish.

‘What about the third shot?’ asked someone.

‘If we follow a rough trajectory from the impact to a point in the field where the suspect’s vehicle was positioned, we see that the third shot passed through the window at about the same height and the same angle as the others. Exactly where the victim had been standing, in other words. So the third shot was probably fired after she’d already started to fall. That’s why it missed.’

‘Could that have been the first shot, rather than the third? I mean a miss, followed by two hits when the shooter got the range?’

‘Possibly. But the other two shots were very accurate. A head shot, and one near the heart. Besides, if you heard a shot and felt a high-velocity bullet whizz past your head, your first instinct would be to dive for cover.’