Brazillian police have arrested 53 people for allegedly stealing $30 million (£16 million) from Internet bank accounts.
The suspects are alleged to have netted the loot by sending out thousands of e-mails containing a trojan virus, capable of reading user passwords and security codes.
The police swoop, which involved 160 policemen, took place across four states in the north of Brazil. According to investigators, 18 of the suspects had been imprisoned for similar offences in the past.
Banks targeted by the scamsters included Banco do Brasil, Bradesco, Caixa Economica Federal, HSBC, Itau, and Unibanco.
Graham Cluley, senior technology consultant for anti-virus firm Sophos says: "The Brazilian authorities should be congratulated for taking swift action against this activity - fifty arrests give some idea of the huge scale of this kind of organised Internet crime."
At a conference in the capital, Brasilia, in September, computer fraud experts said Brazil was now the global capital of hacking and Internet fraud. The amount of money lost in Internet financial fraud in Brazil outstripped that lost through bank robberies, the conference was told.
The latest arrests come amid a worldwide crackdown on con artists operating over the Internet. Earlier this week a dozen people were arrested in Hong Kong in connection with a banking phishing scam that is believed to have netted the fraudsters HK$600,000 (£47,000). UK law enforcement authorities have also pressed criminal charges against the alleged perpetrators of a phishing scam that conned UK banking customers out of hundred of thousands of pounds.