Around 8.30am on Monday, 8 August 2005, the forensics department of the federal police bureau in the Brazilian city of Fortaleza received a phone call. A robbery had apparently taken place at the local Central Bank. Officers grumbled to each other that the interruption to their morning coffee was probably just another missing computer.
Arriving at the scene of the crime, they realised this was no routine job. During the weekend thieves had broken into the bank's vault and stolen a record amount of money undetected and without triggering any of the bank's alarm systems.
The vault that weekend had been full of money, brand new notes, ready to be released into circulation, and old notes that had been withdrawn perhaps to be incinerated. The thieves took only the used notes - the bank had kept no record of their serial numbers. They were untraceable. In all, 164.7m reis (£40m) was taken. The thieves could lay claim to having executed the world's biggest bank robbery. The only bank theft greater was the seizure of a billion dollars of gold and currency some time at the beginning of the Iraqi conflict, though since Saddam Hussein and his cronies allegedly perpetrated this, it could hardly count as a robbery.
It was not just the volume of money taken that was extraordinary, but the manner in which the crime had been pulled off. To break into the vault, the gang dug an 80-metre tunnel, wood panelled and fitted with electric lighting and rudimentary air-conditioning; their final engineering feat had been to drill through a metre of steel-reinforced concrete.
The tunnel's entrance was a block away from the bank in a building that purported to house a business selling artificial grass, but this was really a façade used by the gang to hide their true purpose. They were thorough in creating the illusion, distributing free promotional baseball caps and even taking out adverts.
Fleeing the building, the gang had covered the room from which they worked with white powder to make fingerprinting difficult. The only concrete information the police had was a copy of the identity document that had been used to rent the building. The name of the leaseholder was Paulo Sergio de Souza, and on his identification card there was a photograph of him, bizarrely wearing a hat. Questioning of locals revealed that many people recognised Paulo Sergio, but beyond that, the police knew little. Like Keyser Soze in The Usual Suspects, his name was on everyone's lips but he had disappeared without a trace. He became a folk hero and locals toasted the criminals who had pulled off an apparently perfect "victimless" crime.
By late November last year, certain progress in the case had been made. Thirteen suspects had been arrested, and about 11 per cent of the stolen money recovered. Warrants had been issued for a number of other men with colourful pseudonyms "The German", "The Tortured" and "The Big Digger". On the downside, the man suspected of underwriting the tunnel crime, a drug dealer called Luiz Fernando Ribeiro had been kidnapped and murdered (possibly by corrupt policemen) and the identity of Paulo Sergio remained a mystery.
When the crime was perpetrated, the thieves escaped without using guns. But soon after the investigation began events had turned darker.
On 8 October, exactly two months after the robbery was discovered; 26-year-old Luiz Fernando Ribeiro was kidnapped outside a nightclub in a suburb of Sao Paulo.
A few hours later Marcio Marcio, a key defence lawyer acting in the case, received a panicked call from Fernando's family. They had received a ransom demand and wanted Marcio to act as intermediary.
Marcio met the kidnappers at a suburban petrol station, where they allowed him to speak to Fernando via a walkie-talkie before he handed over more than one million reis (£246,000). The kidnappers departed promising their hostage would arrive later, but Fernando never returned.
In desperation, Fernando's family turned to the police, and revealed they believed he had been kidnapped because he helped finance the Central Bank thieves (such an elaborate robbery had significant overheads), and had received many millions in return. On further investigation it became clear that Fernando was also a big-time drug trafficker and killer.
For Fernando, though, the wheel had turned full circle. Thirteen days later, his bullet-ridden body was found in farmland several hundred miles from Sao Paulo. Investigations later led to the arrest of two police officers for their alleged involvement in the kidnapping.
Marcio was understandably nervous. The kidnap and murder of Fernando could hardly be considered an isolated event. In 2004 alone, 49,587 people were murdered in Brazil, and that rate continues to grow.
In sunny Fortaleza, it is hard to imagine such atrocity. The spectacular beaches seem like a kind of paradise. But when night falls, a different Fortaleza emerges, still beautiful, but with a sizzling underbelly of sleaze fuelled by a huge sex tourism problem. The scene of the crime, a tall brown glass skyscraper in the commercial district of the city, is one of nine regional offices of the Banco Central do Brasil, the Brazilian equivalent of the Bank of England, which controls the flow and supply of money within the economy.
When people talked of the crime being victimless, it was because the stolen money had already been withdrawn from circulation, and was therefore taken not from private accounts but, in effect, from the economy itself. Unsurprisingly, the Central Bank was deeply embarrassed by the publicity surrounding the robbery and refused to comment.
But in the nearby streets, next door to the artificial lawn business from where the thieves purported to operate, is a seedy hotel. The owner, Marcos, is a wild-eyed voluble guy who would not be out of place hustling on the streets of New York city.
"A guy called Paulo Sergio turned up in a van and the place stayed closed for 15 days," he said. "Then he brought some workers, put up the awning and opened up his artificial lawn business."
Up a rickety staircase that leads to the roof, Marcos excitedly pulls slate tiles from the neighbouring building. Through the rafters, bags of earth are visible, stacked on top of each other.
"The one who was being very friendly to everyone around here was called Paulo Sergio. There was once that he told me he was doing some work at the Central Bank, but I didn't suspect anything, because there was no mess."
On the rear balcony, the tower of the Central Bank is in clear view. Two of the timber beams that supported the tunnel are also visible. Marcos hopes to auction them off as memorabilia of the heist.
The crime team from Fortaleza's O Povo newspaper, which recently won the Brazilian equivalent of the Pulitzer Prize for its investigative work on the Central Bank story, made a number of breakthroughs in the case ahead of the police, including the discovery of the house where the money was divided up before being taken out of Fortaleza.
At the courthouse, 13 men are on trial for their part in the crime. Though none of the supposed leaders have yet been detained, six of the men, including a career criminal called Davi da Silva, were caught "red-handed" in possession of the stolen money.
Da Silva's story was all about tunnels. In 2001, he had been involved in the biggest jailbreak in Brazilian history when 108 men escaped via a tunnel from Carandiru penitentiary in Sao Paulo, perhaps the most notorious prison in South America.
There was a certain comic neatness in a felon tunnelling out of jail and then, in effect, tunnelling back in. At the time of his escape Da Silva was serving sentences totalling 80 years. Whatever the outcome of the trial in Fortaleza, he was going nowhere fast. Nonetheless he hired not one, but two lawyers to defend him, including Leandro Vasques, a pudgy-faced young advocate with a curious argument for the defence.
"It's very easy to place responsibility on anyone who happened to have taken part in this theft," he said. "But one also has to ask to what extent the lamentable security arrangements of the Central Bank contributed to the success of the enterprise." Could it really be reasonably claimed - in a crime where the perpetrators dug an 80-metre tunnel to gain access to the bank's vault - that the bank's undoubtedly inadequate alarm systems mitigated the culpability of the thieves?
The media speculated that the crime was orchestrated, not by a rogue gang, but by the leaders of Brazil's most powerful mafia organisation the PCC (Premeiro Comando da Capital). Several of the arrested men were members, and it was thought that much of the money from the crime ended up in the hands of the PCC.
The PCC's principal activity is drug trafficking, but the gang also performs kidnappings and robberies. Little is known about the PCC. But the founder, a man nicknamed Geleia which means "the Big Jelly," said that the gang received a cut of the proceedings of big crimes, whether organised by the leaders of by members lower down.
Geleia has spent most of his life behind bars, and is currently serving time in Brazil's highest-security jail. He has quite a reputation; he was known to have killed men in prison and has committed numerous violent crimes. But he is also known for his political activism, using the PCC's power to fight for improved prison conditions. In 2002, he quit the PCC after a dispute, and is now planning to write a book about his life.
In his cell, wearing a yellow prison jumpsuit, he smiles. But he is nervous about speaking in front of the prison guards. He wants to go somewhere more private, and, in a prison courtyard, unmanacled and able to move about freely, he begins to talk.
"No one is going to rob a bank and not make a contribution [to the PCC]," he said. "But what that is depends on the job. It's not a fixed amount. Two million ... Three million; a good amount."
He joked about several of his friends, "good diggers", who had been connected to the Central Bank robbery but said he knew nothing of Paulo Sergio, the supposed mastermind of the crime. I suspected he knew more, but in his low rasping voice, his final word on the subject was: "I hope the police don't catch Paulo Sergio, he doesn't deserve to be in jail, he deserves to enjoy his life out there with all that money. God bless the money and the person who took it."
From his isolated place in prison, Geleia may have been expressing the sentiments of many other people in Brazil. But the reality was that the "perfect" crime was unlikely to have a fairytale ending.
As the journalists from O Povo said: "This 164 million wasn't divided up between the participants, no way."
"The logic of the crime is capitalist, what you take in one robbery is to finance another robbery, and so it gets bigger, and bigger, and bigger."
'Gold Diggers: The World's Biggest Bank Robbery' will be shown on Friday at 9pm on the Discovery Channel