Ragnar looked at Nick for quite a while, weighing up the problem. Then he said, ‘Who’s Wada?’

‘Kristjan’s Japanese friend. Erla hasn’t heard from her since Sunday.’

‘She told me her name was Abe.’

‘OK. Abe.’ Evidently – and perhaps wisely – Wada had used a pseudonym. ‘We want to know why the police turned up so quickly, Ragnar. The obvious explanation is … you tipped them off.’

‘I didn’t tell anyone anything.’

‘Someone did.’

‘Not necessarily.’ Ragnar glanced over his shoulder, as if afraid they might be overheard, though they were alone on the landing. ‘All right. We’ll talk. This way.’

He led them to the door of his apartment and went in.

It was immediately obvious Ragnar lived as slobbishly as he dressed. Clothes were strewn everywhere and, as they passed the kitchen, Nick glimpsed a stack of unwashed dishes and a teetering tower of crushed pizza boxes.

They followed him into the lounge, which appeared to be the centre of the general chaos. He didn’t offer them a seat as he unloaded his shoulder bag on to a table and took off his parka. The bag brushed against a trio of empty lager bottles, causing them to topple over and roll noisily around, one of them falling to the floor. Ragnar paid no attention.

‘Who is this guy, Erla?’ he asked, nodding towards Nick.

‘I told you.’

‘You told me his name, yeah, but … who is he?’

‘A friend.’

‘Of Martin Caldwell’s,’ Nick cut in.

Ragnar gawked at him. ‘So you’re English, right?’

‘Right.’

‘You remind me of someone. Who is it?’

‘How should I know?’

Ragnar frowned. ‘It’ll come to me.’

‘While it does, why don’t you explain why things went wrong on Sunday night?’

Ragnar looked at Erla. ‘Does Kristjan know you’ve involved this guy?’

‘Just answer his question.’

‘I didn’t rat on Kristjan, OK? Why would I? As the person who got him and Abe into the building, I had more to lose than anyone from them being caught.’

‘So,’ said Nick, ‘what went wrong?’

‘My guess? Some booby trap built into the system. Any attempt to access the files out of hours triggers an alarm. This Emergence shit is even more sensitive than I thought. The office has been like a North Korean interrogation camp these past two days. Real heavy stuff.’

‘What are they worried about? Didn’t the booby trap work properly?’

‘You tell me. The police only caught Kristjan, right? So, did Abe get away with anything?’

‘What’s the consensus among your colleagues?’