‘That’s her, isn’t it?’ said Erika quietly. Moss and Peterson nodded.

‘Okay,’ said Isaac, breaking the silence. ‘Her body was found frozen in the ice. At this early stage I’d hazard – and I repeat, hazard – that she’d been in the water for at least seventy-two hours. The temperature dropped below zero three days ago. Also, her phone was still working when she was found; a young guy who works here heard it ringing.’ He handed Erika an iPhone, bagged up in clear plastic. It had a spray of Swarovski crystals on the cover.

‘Do we know who was ringing?’ asked Erika, seizing the thought of an early lead.

‘No. The battery died shortly after we retrieved it from the water. It’s been dusted for prints, but it’s a mess.’

‘Where’s the guy who found her?’

‘The paramedics are with him in an ambulance by the Visitors’ Centre. He was in a state when uniform arrived on the scene. He’d fallen through the ice on top of the body; vomited, urinated and defecated in shock, so we’re trying to eliminate his DNA fast,’ said Isaac. He moved to the body on the stretcher.

‘Bloating of the face and ligature marks on the neck could indicate strangulation, and her right collar bone is broken,’ he said, and gently used a latex gloved hand to tilt the head. ‘Clumps of hair are missing, roughly around the same patch by each temple.’

‘Whoever did it could have been behind her and pulled at her hair,’ said Moss.

‘Is there evidence of sexual violence?’ asked Erika.

‘I’ll need time to look further. There are weals and scratches on her inner thighs, ribs, and breasts . . .’

He indicated a bloom of red lines under each breast, and carefully placed his hand over to show the imprint of fingers on her rib cage. ‘The wrists are lacerated which could indicate her hands were tied, but her arms weren’t tied when she went into the water. There is also bruising to the back of the head and we found fragments of tooth enamel embedded in the front corner post of the jetty . . . We’re still looking for the remains of the tooth. She could have swallowed it, so I may find it later.’

‘When she went missing, she was wearing pink high heels and had a pink bag. Any sign of those?’ asked Moss.

‘She was only wearing the dress and underwear, but no bra . . . no shoes.’ Isaac carefully lifted her legs. ‘The heels of her feet are badly lacerated.’

‘Dragged barefoot,’ said Erika, recoiling at the sight of her feet, angrily scraped and split, the flesh underneath pink.

‘One of our divers did pull this out of the water.’ Isaac handed Erika a small clear plastic bag. It contained a driving licence ID card. They regarded the photo, silent for a moment.

‘That’s an intense photo. It’s like she’s there, staring at us from beyond the grave,’ said Peterson.

Erika thought he was right. Often in ID pictures the eyes were glazed over, or the subject looked a little trapped in the headlights, but Andrea had a confident stare.

‘Jesus,’ said Erika, looking from the photo of Andrea to the dead body, wide-eyed and filthy on the stretcher. ‘How soon can you establish an exact cause of death?’

‘I’ve given you enough to go on. I’ll need to do the autopsy,’ bristled Isaac.

‘Which you’ll do today,’ said Erika, fixing him with a stare.

‘Yes. Today,’ said Isaac.

The grounds were quiet outside the forensics tent. The snow had stopped falling, and a group of uniformed officers were silently combing their way around the lake, white bunching up around their dark legs as they waded through the drifts of snow.

Erika took out her phone and called Marsh. ‘Sir. It’s Andrea Douglas-Brown,’ she said.

There was a pause. ‘Shit.’

‘I’m just on my way to talk to the boy who found her, and then I’ll go and inform the parents,’ said Erika.

‘Your thoughts? Foster?’

‘Without a doubt we’re looking at murder, perhaps rape with strangulation or drowning. Everything I have is on its way to the guys back at the nick.’

‘Do we have any suspects in view?’

‘No, sir. I’m hitting the ground running as it is. We need to organise a formal ID with the family. Forensics are going straight from the scene to do an autopsy so I’ll keep you posted on the arrangements for that.’

‘If I can tell the media we have a suspect . . .’ started Marsh.

‘Yes, sir. I know. Talking to the family is our first line of enquiry. There is a high chance she knew the killer. When she went missing there were no witnesses, no one saw her being snatched. She could have met the killer here.’