Spain's civil guard on Wednesday arrested five people suspected of defrauding Internet users by using hidden software to divert their dialup calls to premium high-cost phone numbers.
The group may have made over 35 million euros ($42 million) from a scheme that could have affected more than 45,000 people across the country, officials said in a statement.
They said those arrested, all aged between 30 and 39, had set up more than 150 music, pornography, car, leisure and travel websites to carry out the fraud.
"When web surfers opened these pages, a programme of the "dialer" type was secretly installed and hidden on their computers, which diverted their connections without express consent," the civil guard said in a statement.
The phone numbers cost around one euro a minute to call, and some fraud victims received phone bills for over 3,000 euros.
Police uncovered the server for the pages in the northwestern city of Vigo, while the business headquarters was in Madrid.
