‘Come into the kitchen. It’s the warmest room.’

An aroma of coffee had filled the kitchen in Tallgren’s absence. An electric percolator stood ready on the crumb-strewn worktop. He grabbed a couple of mugs and waved Eusden to the table opposite, where a crumpled copy of Helsingin Sanomat lay, folded open at the page in the business section Eusden had seen earlier, with the photograph of Tolmar Aksden and Arto Falenius. Tallgren pushed it aside as he delivered their coffees.

‘Black OK? I’m out of milk.’

‘No problem.’

‘And cream.’ Tallgren nodded down at the newspaper. ‘Looks like they got it all.’

‘Do you regret tangling with them?’

‘You bet.’ Tallgren took a reflective sip of coffee, then sat down and folded the paper back on itself. The faces of Aksden and Falenius obligingly vanished. He smiled. ‘I’ve seen enough of that pair.’

‘What can you-’

‘Hold on.’ Tallgren raised his hand. ‘This is how it’s going to work, Richard. You give me the full story of what brought you here. The whole thing. Then, if I’m convinced you’re not… some kind of spy for those bastards… I’ll tell you everything I know. You’re sitting here with me because of Timo. No other reason. I don’t know you. He says I can trust you. OK. But that’s a two-way street. And you’ve got to trust me first. Do we have a deal?’

It was a relief in many ways to have no choice but to share everything he knew with somebody else. Tallgren sipped his coffee and smoked his way through a couple of roll-ups while Eusden recounted the events that had brought him to Suomenlinna. He took out the double-headed-eagle envelope and showed Tallgren the piece of paper with the fingerprints on it. He talked about Marty and Clem and all the people he had met in the course of one desperate week. He held nothing back. He laid it all on the line.

When he had finished, Tallgren topped up their coffees and said, simply, ‘It’s worse than I thought.’

‘I’ll assume you know as much Finnish history as the average non-Finn, Richard, which is zero,’ said Tallgren. ‘So, I’ll try to keep it simple. Sweden surrendered Finland to Russia in 1809, but Tsar Alexander the First granted the Finns self-government. He knew he’d have too much trouble with us otherwise. The Grand Duchy of Finland, as it was called, was part of the Russian Empire, but not part of Russia. It ran its own affairs. That made it a haven for anti-Tsarist revolutionaries – Bolsheviks, Mensheviks, anarchists, nihilists – in the years before the First World War. It became Lenin’s second home. He and Stalin met for the first time at a Bolshevik conference in Tampere in 1905.

‘I set out to write a full study of the revolutionaries active in Finland during that period. It was a fascinating subject. I never thought it was dangerous as well. The Falenius Bank, as Saukko was called back then, was mentioned in a lot of correspondence as a source of loans to such people. Well, Arto Falenius was willing to admit his grandfather lent money to revolutionaries, though he denied they were gifts in effect, never repaid. He also denied Paavo sheltered mutineers who took part in a short-lived Red uprising here on Suomenlinna in 1906. It was odd. The evidence was clear and I couldn’t see a problem. Paavo Falenius was a socialist sympathizer. Good publicity, I’d have thought.

‘Then I came across some other information that confused the picture. Lots of new stuff was leaking out of the Soviet Union around then thanks to glasnost. It turned out from some of it that Lenin suspected Paavo Falenius was a double agent, feeding information about the revolutionary groups to the Tsarist government in St Petersburg. True? I never found out for sure, because that was when I really got Arto’s attention, by probing his grandfather’s relationship with a shadowy character called Karl Vanting.

‘Vanting was Danish, born in Copenhagen in 1884. He moved to Helsinki in 1905 specially to offer his services to Lenin as an active revolutionary. He played a big part in organizing the 1906 mutiny and a general strike the same year. The story was that he was a bitter enemy of the Romanovs because he was an illegitimate son of Tsar Alexander the Third. It could be true. There was supposed to be a resemblance. And my researches showed his mother worked as a maid in the Danish royal palace of Fredensborg. She was dismissed in December 1883. Karl was born five months later. Pregnancy was probably the reason for her dismissal. The Tsar and the Tsarina, Dagmar, went to Fredensborg with their children every summer to visit their Danish relatives. So, the timing fits. Karl’s mother married a Copenhagen shopkeeper called Vanting in 1885 and the boy took his stepfather’s name.

‘The same material that quoted Lenin as suspecting Paavo Falenius of working for the other side mentioned Vanting as his alleged confederate. This is where it gets murky. Vanting left Helsinki in 1909, destination unknown. It took a lot of work to follow his tracks. He dropped out of revolutionary politics altogether and turned up on the Caribbean island of St Thomas, working as a clerk for the aide-de-camp to the Governor of the Danish Virgin Islands. The aide-de-camp’s name was Hakon Nydahl. Denmark sold their Virgin Islands colony to the United States in 1917 and Nydahl went home. Vanting didn’t go with him. He stayed on, working for the new American administration. Then, in the spring of 1918, he got himself attached to a US regiment sent to intervene in the Russian Civil War. He spoke quite good Russian and they were short of interpreters.

‘The Russian Civil War was the Whites against the Reds – crudely speaking, Tsarists versus Bolsheviks – in the aftermath of the Revolution, complicated by parts of the old Empire trying to break away and British, French, German and American forces trying to grab territory and/or stop the Reds winning. Plus rescue the Tsar – if they could. Finland declared independence from Russia at the end of 1917 and then had its own Reds against Whites Civil War. Unlike in Russia, the Whites won, with a little help from the Germans. It was all over by May 1918. Thousands had died. And thousands of Reds had been taken prisoner. This is where they were held. Here on Suomenlinna. The fortress became a prison.

‘What’s this got to do with Karl Vanting? Well, one day in October 1918, two people arrived in Suomenlinna in a small boat they said they’d rowed across the Gulf of Finland from Russia. One of them was Vanting. The other was a lad in his early teens. Vanting didn’t say anything about serving in the American army and he claimed he didn’t know what had been happening in Finland. Unfortunately for him, the prison commandant remembered him as a Red revolutionary. He and the lad – whose name wasn’t recorded – were locked up.

‘Conditions here in 1918 were terrible. Overcrowding. Disease. Famine. Vanting couldn’t have chosen a worse place to land. But he wasn’t here for long. After a few weeks, he and his companion were released on the recognizance of Paavo Falenius. And then… they dropped out of sight.

‘It gets even murkier now. Like Timo told you, the big unanswered question about Saukko Bank is where their influx of capital in the early nineteen twenties came from. Well, what you’ve found out fills in the gaps in a theory I thought was really off-the-wall when I first developed it, but now… fits together like Lego. A Danish invention, no? Lege godt. To play well. And they did play it well.

‘Paavo Falenius was a double agent. Not much doubt about it. Maybe the best kind. The kind both sides trust so completely you have to ask: which side was he really on? He was born in 1869. Studied law at St Petersburg University. One of his fellow students was Peter Lvovich Bark, who also went into banking and was the Russian Minister of Finance from 1914 until the Revolution. He fled to England afterwards, where he became Sir Peter Bark, a director of the Bank of England. Strange, no? But consider. Bark acted as executor for the Tsar’s estate after his presumed death. Only he knew how much money there was and where it was. Falenius was an old friend of his. I found photographs of them together in a university rowing team and later at banking dinners in Helsinki and St Petersburg.