Brazilian federal police have arrested 53 suspects on charges of stealing £45m from online banking customers.
Police said that hackers sent identity theft emails, a technique known as phishing, to online banking customers in a bid to capture their bank account details. They would then use the details to access bank accounts.
Victims of the online fraud also opened email attachments containing a Trojan horse that stored and sent their bank account details to the suspected hackers. The Brazilian Federal Police said that thieves stole a total of 240m Brazilian reais (£45m) from nationals.
"They used phishing techniques to make the scam work," said Joviel Britto, a spokesman for the Brazilian Federal Police. "They sent an email and after you put your information in, they could pick up money from your bank account."
Yesterday, the police seized cars and computers from suspects in four northern states of Brazil. Reports stated that most of the suspects were under 25 years old. Investigators said that 18 of the suspects had already been imprisoned for similar offences in the past. 160 policemen took part in the operation.
Last month, security experts said that Brazil was a hacking hot spot of the world. According to security company Sophos, banks that were targeted in the Trojan horse attacks included Banco do Brasil, HSBC and Unibanco.