There was a pause. ‘She wasn’t in when we called,’ he told her. ‘We’ve left messages with her to get in touch as a matter of urgency.’

She felt her panic rise. ‘But shouldn’t you – I mean, what if she knows something? What if she’s got something to do with this? Whoever did this last night must have had a key to the main door – what if it was someone who lived here, in the building? Maybe she’s got some weird kind of obsession with Luke, maybe—’

‘We have no reason to think that at this stage,’ Anderson talked over her in the same, infuriatingly calm manner. ‘We will speak to her though, Clara, I promise. We are dealing with it. In the meantime, I would suggest you stay somewhere else for a while, at least for the foreseeable future.’ She felt a little as she did as a child, when her father told her to go to her room to calm down.

‘But—’ she said.

‘I called to remind you there’s a press conference scheduled for later today,’ he went on. ‘MIT wondered if you’d be prepared to say a few words – talk about Luke, about the sort of person he is …’

She closed her eyes. She couldn’t think of anything she’d rather do less. ‘Is there any news about the van?’ she asked.

‘Not yet, no. I’m sorry, Clara. I know this must be very frustrating for you, but we are confident that …’

She sank on to the sofa, her legs suddenly weak. She listened as he reassured her they were doing everything they possibly could, and when she hung up she stared blankly down at her phone, trying and failing to process the terrifying and utterly surreal possibility that the man she loved might die – might already have been murdered.

Later, she tried to soothe herself with the mechanical, mindless act of righting chairs and refilling drawers, and it was while she was in the tiny, windowless room they used as an office that she discovered the photographs. The metal filing cabinet Luke kept his personal documents in had been upturned, its contents rifled through and scattered across the floor. She began stuffing the various invoices and bank statements back into their slots, but when she attempted to slide the drawer into place she realized that she couldn’t. Frowning, she reached in and felt around until she located the obstruction – a large manila envelope that had become caught beneath it. Pulling it out she found three photographs inside – all of them of the same young woman.