‘I can’t see anything, sir.’

The screen was shiny and clear. No dust. No words.

‘I don’t believe this, Kirsty must have cleaned it. Oh, that stupid…’ He bit his tongue.

‘Sir. You’re shaking. Are you sure you don’t want a cup of tea?’

‘Will you shut up about tea!’

The policeman’s mouth formed an O of surprise. Jamie saw his hand go beneath his jacket, ready in case Jamie got violent. How the hell had it got to this point, the point where he was yelling at a policeman? This was all wrong. He sat down again and the policeman relaxed.

‘I’m sorry. I’m really sorry.’ He lifted his head. ‘I’m so stressed out by all this. I promise you, somebody was in here, and I know who it was. My downstairs neighbour, Chris Newton. He works with computers. He might know how to program a virus. If not, he’ll certainly know someone who could.’

‘What do you do for a living, Mr Knight.’

‘Well, I work with computers too.’

‘So you also know people who could create a virus?’

‘Yes, but…’ He trailed off.

‘And would you know how to do it yourself?’

‘I suppose so.’

The policeman tapped his notebook with his pencil. ‘How did this person get into the flat? You say there was no sign of forced entry. I take it all the doors and windows were locked.’

‘Of course they were. And I don’t know how he could have got in. Maybe he’s got a key. He’s got a key for the outer door.’ A thought sprung into his head. ‘Maybe the previous occupants gave him a spare key in case they got locked out.’

‘It’s possible.’

‘Yes. That explains it! That’s why there’s no sign of anyone breaking in.’

‘Well, can you ask the previous occupants? Or give me their name and telephone number and I’ll do it.’

‘I don’t know their telephone number. In fact, I wouldn’t have the first idea about how to contact them. They were gone before we even looked at the flat. The sale was handled entirely by their solicitor and the estate agent.’

‘You must know their name.’

‘I can’t remember it. It was a foreign-sounding name, I remember that.’

‘Because if we can contact these people and they tell us that they did indeed give a key to your neighbours downstairs, that’s evidence that they had the means to get in here.’

Jamie brightened at the sound of that word. Evidence. And then a chill went through him. If Lucy and Chris did have a key, who knows how many times they had been in the flat?

‘I’ll find the house buying documents. Wait there.’