Anderson switched off the computer and took the seat next to hers, his eyes focused on her face. ‘We’re doing everything we can to find the van, Clara. And we will find it. But in the meantime we’re appealing for witnesses who might have been in the vicinity when Luke disappeared.’

Panic climbed in her chest. ‘What about the emails?’ she asked at last. ‘Do you have any idea who sent them?’

‘Not yet, no. We’ve traced them to several different servers belonging to various internet cafés across London. Not one of them had working CCTV, which might be coincidence but probably isn’t. We still have no way of knowing whether the person who sent them is connected to Luke’s disappearance. What we do know is that Luke hasn’t withdrawn any money from his account since last Monday, nor did he take out any significant sums in the days leading up to his disappearance, which indicates that he hadn’t been planning to go anywhere for any length of time. As you know, he didn’t take his passport or credit card.’

It was only then that she remembered Luke’s sweatshirt. ‘I saw something,’ she said. ‘In my neighbour’s flat.’

Anderson listened patiently as she told her story. ‘It might not have been his, of course,’ she added, ‘but it’s pretty distinctive.’ Her eyes searched the detective’s face uncertainly. ‘I don’t know if …’

‘We’ll look into it,’ Anderson told her as he got up and nodded at her to follow. ‘We were intending to speak to your neighbours again anyway. I’ll let you know what we find out.’

And that was it. She was alone again, standing in the street, looking back at the black bricks of the police station. She turned and began to walk home. Had Luke known the driver of the van? If not, why did he get in it? If it was someone he knew, had he known the van was stolen? It seemed so unlikely – Luke wasn’t the law-breaking type, and as far as she was aware, he didn’t know any criminals. But if he hadn’t known the driver, then why did he get in the van? Had he been forced to? In central London, while it was still fairly light out? That didn’t seem likely either. She jumped from possibility to possibility, but came up with nothing.