Court documents in the landmark case in Detroit describe a nearly inscrutable puzzle of corporate identities, bank accounts and electronic storefronts in one alleged spam operation.
At one point, investigators said, packages were sometimes delivered to a restaurant, where a greeter accepted them and passed them along to one defendant.
Officials at the Federal Trade Commission, who planned to announce the arrests in Washington on Thursday, told U.S. postal investigators they had received more than 10,000 complaints about unwanted e-mails sent by the defendants.
Court records identified the defendants as Daniel J. Lin, James J. Lin, Mark M. Sadek and Christopher Chung of West Bloomfield, Mich., near Detroit.
They were accused of disguising their identities in hundreds of thousands of sales pitches for fraudulent weight-loss products and delivering e-mails by bouncing messages through unprotected relay computers on the Internet.
Chung and Sadek appeared in U.S. District Court and were released on unsecured bonds, said Gina Balaya, a spokeswoman for the U.S. Attorney's Office. The Lins have not been arrested.
Sadek's lawyer, James L. Feinberg, said U.S. agents arrived at Sadek's home early in the morning "out of the clear blue" and arrested him.
"He was absolutely shocked," Feinberg said. He said Sadek will plead not guilty to the criminal charges, in what will be the first-ever court case of this type.
"No one's done this before," said Feinberg. "It will be fun - not for my client - but for me professionally."
The Lins and Chung could not be located at any of the addresses or telephone numbers listed in the court documents.
Authorities said their company sold a weight-loss patch under the corporate names AIT Herbal, Avatar Nutrition, Phoenix Avatar and others. The company allegedly operated out of Detroit and nearby communities of West Bloomfield and Birmingham.
"These people were sending spam e-mails to at least a million people," Balaya said.
Investigators said they consulted Dr. Michael D. Jensen, a medical professor at the Mayo Medical School, who confirmed that ingredients in the weight-loss product sold in the disputed e-mails wouldn't work.
The "can spam" legislation, which went into effect Jan. 1, requires unsolicited e-mails to include a mechanism so recipients can indicate they do not want future mass mailings.
By Ted Bridis and Adrienne Schwisow