‘You don’t want to do it.’

She doesn’t turn. She knows Robin’s standing behind her. She knows what he’s implying.

‘If I’d asked you that two years ago, in that petrol station, what would you have said?’ she whispers back. Now she turns, looking at her boss. Deep lines appear on his forehead as his eyebrows draw together. His shoulders slump. ‘He was drunk, Robin. Steph confirmed it. He was out drink-driving that day.’

He stops. He blinks, once, twice. She knows there would have been no hesitation in his mind.

‘Freya, listen to me.’ Robin stares right at her. ‘You may think this will be okay. That Amy Miller deserves it. That she killed Jonathan, and it’s right you get this revenge. But however strongly you feel it, nothing can prepare you for the reality of taking someone’s life.’ He stops, pressing his knuckles against his downturned mouth. She sees his jaw clench, holding back the emotion. ‘It takes a part of you, too. That guilt, it eats away at you, until there’s nothing left.’

Freya turns back to Amy Miller. ‘She can’t get away with this,’ she whispers. ‘She can’t.’

She feels gentle hands on her shoulders. ‘We’ll get her,’ Robin says. ‘We will.’

Freya notices him step away, his reassuring contact missed when it’s gone. And along with it, her intention to do harm to Amy Miller. She turns away from Amy’s prostrate body, and watches Robin. He’s facing the bookcase now, staring at the same spot where they did that first search all those weeks ago. Robin reaches forward and takes Jon’s economics textbook from the bookcase. He glances to Freya, then opens it.

In the hollowed-out centre, where the camera was concealed before, is a small black memory stick. He takes it between two gloved fingers.

‘She has a sense of humour, if nothing else,’ Robin says.

Amy’s cleanliness works in their favour: they start from the kitchen, with bleach and cloths and antibacterial spray, erasing every shoe mark and fingerprint. Any sign they were in the house. Freya wipes down the boxes of pills, the whisky bottle, the cupboards, making sure everything shines. Exactly how Amy would have wanted it.

They plump up the cushions in the living room, carry their whisky glasses into the kitchen and wash them up. Robin collects a bin liner from a drawer.

The two of them walk towards the front door, wiping down handles, light switches, door frames. In the hallway, they pull off their white crime scene suits, putting them in the bin liner with the used cloths and their gloves and masks. They pull the front door shut and walk quietly out to the car. Nobody sees them leave. The neighbours are away. The road is empty.

They leave Amy Miller unconscious on the sofa.

All traces of them have gone.