Seven individuals and two companies were named in the suit, including alleged ring leader Leo Kuvayev. Operating from Russia and suburbs in Boston, the group is accused of sending illegal spam that linked to web sites selling pirated software, phony prescription drugs, and mortgages.
In a press conference, Reilly described the operation as "one of the largest internet spam gangs in this country, if not the world."
The operation had serious public safety implications because the emails linked to web sites that pedaled counterfeit and unapproved brand name drugs such as Vioxx, he said.
"Our goal is to shut this ring down and put them out of business," Reilly said.
Investigators do not know Kuvayev's exact whereabouts, he said, adding that the case remains under investigation.
The group used domain names registered in Monaco, Australia, and France, and servers in China, Korea, Brazil, and Taiwan, according to the lawsuit.
"We need to cut spam off its source. If we can stop it there, we can stop the con games it's enabling," said Brad Smith, senior vice president, general counsel for Microsoft, which helped investigate the case.
In one three-week period last year, open MSN Hotmail accounts used to trap spam received more than 45,000 emails from the spam ring, Smith said. Extrapolating from that, the group has likely been sending hundreds of millions of emails each month, he added.
Cooperation between the private sector and government is essential for dealing with the difficult problem of spam, Smith said.
This is the latest spam case filed by a state attorney general. Last month, California Attorney General Bill Lockyer and the Federal Trade Commission sued an alleged spam operation that bombarded internet users with illegal emails touting mortgage services and travel deals.