A man who allegedly operated an international network of dial-a-porn and other telephone services is under investigation for tax evasion, according to documents filed in federal court.

No charges have been filed against A. Joel Eisenberg, 56. But FBI and Internal Revenue Service agents served search warrants Friday on Eisenberg's house and Seattle offices, seizing business records, other documents and computer equipment, the Seattle Post-Intelligencer reported Tuesday.The investigation involves a Seattle-based company, Megaquest, which allegedly is operated by Eisenberg and a Los Angeles woman, Betsy Superfon, a name authorities believe is a pseudonym, the Post-Intelligencer reported based on documents filed Monday.

Megaquest has operated phone services in Utah, Washington, Oregon, California, Colorado, New Mexico, Minnesota, Michigan, Georgia, North Carolina, Louisiana, Massachusetts, Connecticut and Mississippi, Vargas' affidavit said.

Foreign operations have included the United Kingdom, Germany, the Netherlands, Belgium, France, Brazil, Australia and Canada.

Nick Selby, a Palo Alto, Calif., attorney representing the company, said Monday that Megaquest denies any wrongdoing.

"For all I know, an investigation is being brought because of the controversial reputation" of Megaquest, Selby said.

Assistant U.S. Attorney Harry McCarthy said the investigation involved allegations of criminal conduct, not the content of the telephone services.

Megaquest controls at least 82 different entities that provide dial-a-porn and other telephone information services in the United States and several foreign countries, IRS Special Agent Gary Vargas said in an affidavit used to obtain the search warrants.

Vargas said IRS records relating to 47 of the entities for 1986, 1987, 1988 and 1989 showed gross receipts of $126 million. An investigation revealed Megaquest earned gross receipts "far in excess" of those amounts, the affidavit said.