US-based ISP EarthLink claims that its investigation into the source of millions of phishing emails has helped law enforcement agents break up an alleged identity theft ring.

A federal grand jury in New Haven, Connecticut returned an indictment on 20 September charging six individuals with identity theft, conspiracy and fraud in connection with email and access devices.

The charges follow a 12-month investigation by EarthLink's abuse team. The ISP began identifying phishing emails on its network in May 2005.

The messages used a variety of methods including fake greeting cards, bogus prizes and 'account cancellation' messages to trick consumers into providing credit card numbers and other personal information.

EarthLink's abuse team shut down the accounts sending the fraudulent emails, and captured evidence about the emails' origins for law enforcement agencies.

Phishing emails typically instruct consumers to click on a link which looks like a real corporate website and input personal information.

The fake website then steals passwords, email addresses, credit card numbers and other information.

"Phishing sites are a dangerous and fast-growing type of identity theft," said Lindsey Wegrzyn, operations security enforcement advisor at EarthLink.

"Searching for the origins of these hoaxes, and providing evidence to law enforcement, are part of EarthLink's ongoing effort to put spammers out of business and protect the integrity of the internet."