‘Good boy, Bertie,’ she said, in as friendly a tone as she could manage, crouching and holding out her hand towards the dog. She hoped its behaviour was born out of loyalty rather than belligerence. The dog eyed her dubiously, then rushed off to challenge a dog walker, a silver-haired gent with a golden labrador on a lead, hurrying from the opposite direction. The boxer’s barking and stance caused the man to stop, and shorten the lead on his own pet.

‘Did the dog attack her? Is she all right?’ he asked.

Kirsty shook her head. It was the answer to both questions. Her last two strides had brought her within three yards and confirmed her worst fears. There was blood everywhere, spattered across the snow, pooling on the path next to the woman. The ball thrower lay to her right, just out of reach of her open hand, while the dog’s leather lead was grasped firmly in her left fist. She had dark red nail varnish, and several rings. But this was no dog attack. The woman was lying face up, her brown eyes wide in shock, her mouth open, unmoving. Snowflakes on her eyelashes. The side of her skull had been smashed in, her hair matted in the contents, a pink slush already forming beneath it. It was clear she had suffered many grievous blows.

‘She’s dead, stay well back,’ Kirsty said, eyeing the dog, which was repeatedly investigating the body of his mistress, its paws making yet another obscuring track across the blood-spattered snow.

‘We better call the police,’ he said.

Of course.

As if to remind her, a ringtone sounded loudly nearby, demanding attention. The dead woman’s phone. Ringing and ringing in insistent jollity. Someone trying to reach her. Too late. Someone who would never get to talk to her, to ask her a question. A humanising reminder that this person had been part of somebody’s life.

And just then, the snow stopped.

The dog, having barked at everybody, orbited the body on a fast elliptical run, periodically stopping and scanning the horizon, as if seeking the assailant. On a nearby pass, Kirsty lunged forward and grabbed his collar. The animal looked up at her accusingly, but did not struggle. With a jolt she realised that this snowy tableau, a five yard radius from the body, had captured every clue a crime scene investigator could hope for. A bicycle track within three yards of the body, signs of a dismount, several footprints, all of which were vital though transient clues to what had just occurred. They had to be preserved if at all possible.

She turned to the man. ‘Actually, would you ring?’ The man nodded, and pulled his own dog back just as a Jack Russell terrier bounded over, romped past the boxer and began to sniff the body. ‘For God’s sake,’ Kirsty shouted; she struggled to prevent the boxer tackling the terrier, whose owner, a middle-aged woman with a down gilet and a headscarf, was still a hundred yards away.