Federal and state law enforcement agencies have teamed together in recent weeks to arrest or charge dozens of people with crimes related to online scams, the New York Times reported.

Since Congress passed a law last year that calls for fines and prison sentences for those convicted of sending fake e-mails, efforts have multiplied to fight spammers. Some Internet abusers send millions of junk e-mail messages; others commit identity theft; some perpetrate credit card fraud and other financial crimes. Still, spam makes up 65 percent of all e-mail, according to Symantec, a company that makes a widely used spam filter.

"We felt that the key to the new law was enforcement," said H. Robert Wientzen, who recently stepped down as the president of the Direct Marketing Association and is involved in the anti-spam campaign. "We want spammers to realize that spam is not a free game for them and that they face real penalties if they continue."

The Direct Marketing Association has contributed $500,000 to the enforcement effort in the belief that spammers undermine the public's trust in e-mail as a commercial medium.

In a separate operation, federal agents conducted raids in Texas, New York and Wisconsin on Wednesday to crack down on the theft of copyrighted materials through the Internet. Charges are likely to be filed later, CNN reported.

The Internet fraud operation, called “Operation Slam Spam,” has built a database of known spammers, drawing from law enforcement agencies and private companies. It has also used online decoys to catch spammers and has purchased products advertised in spam messages to trace financial records to their sources.

The cases are almost always complex and lead to others involved in spam and other crimes, Steve Linford, director of the Spamhaus Project, told the New York Times.

"These cases never end," said Linford, who works with law enforcement agencies. "When they seize a whole bunch of computers from one gang, they normally see a lot of information that leads to another gang."

While it's not clear whether the increase in criminal prosecutions will make much of a difference, Linford thinks it may slow the flood of junk e-mail, at least temporarily.

"Spammers believe that they will never be caught,'' Linford said. "If they get 10, 20, 30 well-known spammers, the rest of the spam community will start to notice. Any spammers who can be made to give up because they think the F.B.I. is getting too close is very good for us.''