American investigators have shut down an international criminal network they claim is responsible for up to a third of all spam email on the internet.
After a protracted investigation between the US Federal Trade Commission (FTC) and police in other countries, courts in Illinois and New Zealand have frozen the assets of New Zealander Lance Atkinson and Texas-based Jody Smith. They are accused of making millions by bombarding people with emails offering illegal drugs and fake medical remedies.
The duo are believed to be part of a well-known group of spammers known as the HerbalKing gang, who have sent enormous numbers of unwanted messages over the past three years.
'The defendants recruited spammers around the world to send billions of spam messages,' the FTC said in a statement yesterday. 'Their enterprise included participants in Australia, New Zealand, China, Russia, Canada and the United States.'
According to FTC officials, Atkinson and Smith used spam emails to promote drugs for sexual dysfunction, penis enlargement and weight loss - all of which were sold without a licence or did not live up to the claims made.
The duo are believed to have used a string of up to 35,000 hacked computers around the world - known as a botnet - to send up to 10 billion spam messages a day. As many as three million complaints had been made about their messages.
Documents filed in the case name the pair, as well as four companies they control, and accused them of clearing as much as $400,000 in Visa charges alone in a month. A sequence of injunctions and restraining orders prevent them from continuing to do business while the case is underway.
According to the campaigning organisation Spamhaus, HerbalKing is an 'infamous' group that has been operating since at least 2005, which was ranked as the most prolific spam gang on the internet last year.
Both Smith and Atkinson - along with his brother Shane - are well-known spammers, and have been involved previously in cases brought under America's CAN-SPAM act, which makes it illegal to send large amounts of unsolicited email in this way.
Three years ago Atkinson was fined $2.2m after he was found guilty of running a similar programme marketing herbal products over email.
The news marks the latest in a string of cases brought by US federal investigators against spam marketers
Earlier this year Robert Soloway, from Seattle, was sentenced to 47 months in prison and ordered to repay $700,000 which he had taken as a result of his activities.
And this summer notorious spammer Sanford Wallace - known as 'Spamford' - was fined a record $230m for attacking MySpace users and using the social networking site to send porn spam to millions of users.
Although spam is usually most associated with clumsy attempts to sell unwanted goods, one official said that the spammers had improved their methods of attack in order to carry on fooling people.
'These sites are really professionally constructed,' Steve Baker, the FTC's Midwest Region director, told the Associated Press.
Other experts warned that other spammers would be likely to take the place of the HerbalKing gang immediately.
'Anyone hoping that they might find less spam in their email tomorrow morning is probably going to be in for a disappointment,' said Graham Cluley, senior technology consultant at internet security company Sophos.
'It's unlikely that action like this is going to result in a dramatic drop in the amount of spam you encounter - but the more action that is taken to crack down on criminal spammers, the better for all of us.'