WASHINGTON -- Federal authorities arrested and charged two Detroit-area men Wednesday with criminal violations of the Can Spam Act, the landmark anti-spam legislation signed into law last December by President Bush.

The Federal Trade Commission (FTC) charged Phoenix Avatar and its principals with sending illegal spam to sell bogus diet patches. The e-mail did not include an opt-out provision and used innocent third parties in the "reply to" line, a spamming tactic known as spoofing. Both practices are violations of the Can Spam Act.

At a media briefing Thursday, the FTC said Phoenix Avatar sent almost a half million e-mails between January and April and grossed more than $100,000 a month in the operation.

The Michigan U.S. Attorney's Office charged Christopher M. Chung and Mark M. Sadek of West Bloomfield, Mich., with criminal violations of federal mail fraud laws, as well as criminal violations of the Can Spam Act.

Chung, Sadek and two other defendants who have not been arrested yet face up to 20 years in prison on the mail fraud charges and as many as five years on the Can Spam violations. In addition, the FTC won court approval Wednesday to freeze Phoenix Avatar's assets and to bar further spamming by the company until the charges are resolved.

"The cyber scam artists who exploit the Internet for commercial gain should take notice," Jeffrey Collins, the U.S. Attorney for the Eastern District of Michigan, said at the Washington press conference. "Federal law now makes it a felony to use falsehood and deception to hide the origin of the spam messages hawking your fraudulent wares."

In a second case, the FTC filed charges against Global Web Productions, a spam enterprise also selling questionable diet patches, which operates out of Australia and New Zealand. The FTC said Global Web sent approximately 400,000 spam messages between January and April.

Both Avatar and Global Web have been identified by the anti-spam organization Spamhaus as being some of the largest spammers in the world.

"They used the spam to drive traffic to their Web sites," said Howard Beales, the FTC's director of consumer protection. "They used false header info, had no opt-out and there was no physical address in the e-mail. It was a spam dunk."

In the Phoenix Avatar case, consumers who wanted to purchase the products clicked on a hyperlink in the message and were connected to one of the defendants' many sites. The FTC alleges the claims made for the diet patches are false and that the patches, which sell for $59.95, will have no effect at all.

When spam was undeliverable and bounced back, "tens of thousands" of messages went to unwitting third parties, sometimes resulting in the third parties being mislabeled as spammers themselves.

Global Web not only advertised bogus diet patches through its spam, it also hawked human growth hormone products that could "maintain [a user's] appearance and current biological age for the next 10 to 20 years." According to papers filed with the court, the products did not contain growth hormones of any sort. Global Web sold the diet patches for $80.90 and the false growth hormone products for $74.95.

In both cases, the FTC introduced as evidence thousands of examples of the defendants spoofing a wide array of victims, including AOL and Microsoft.