More from this series Part One Canada's production of marijuana challenges the US DEA Part Two Misha Glenny goes to the Balkans to follow the trail of smuggled cigarettes. Part Three South Africa's private security sector has boomed as people become obsessed with personal safety. Part Four Misha Glenny goes to Brazil which produces more cyber-criminals than any other nation.

Misha's photos from the Balkans

The fastest growing sector of global organised crime is cyber-crime. Internet banking and credit-card fraud is increasing at a rate of about 40 percent per year and is estimated to be worth around $100 billion annually.

Brazil produces more cyber-criminals than any other nation.

As Misha Glenny finds out in the final part of this series, How Crime Took on the World, there are particular reasons for this - not least the fact that Brazil has one of the most sophisticated banking systems in the world. This is because for many years, the Brazilians operated a protectionist economic system, and therefore developed its own highly skilled IT workforce.

And there is a rich, tempting market for cyber criminals in Brazil. Although only 14 percent of the population are regular internet users, that's still close to 30 million people. Three-quarters of them do the bulk of their financial transactions on line.

In Sao Paulo Misha meets some of Brazil's spammers and hackers. He has online conversations with a cyber criminal known as 'Slack' whose group makes over $7,000 a month - a very sizeable sum in this developing nation. He also meets 'Fabio', a poor man from one of the favelas who is unashamedly learning the skills of a hacker in order to commit crime.

At the Federal Police headquarters, the officer in charge tells Misha they receive an average of thirty reports of cyber crime a day - far more than the cyber unit can deal with. And the fear is that as more and more people become computer literate, there will be a still further exponential rise in this quintessential crime for the 21st century.

Misha Glenny is the author of McMafia: A Journey Through the Global Criminal Underworld.

First broadcast Monday 19 May 2008.