Authorities are starting to return $55 million swindled from 8,500 victims of an internet-based Ponzi scheme, federal prosecutors say.

The funds being returned were seized by federal agents in connection with a criminal investigation of Thomas A. Bowdoin Jr., a Florida resident who owned and operated “AdSurfDaily,” a purported on-line advertising firm.

Authorities allege that “AdSurfDaily” was actually nothing more than a Internet-age Ponzi scheme that operated from 2006 through 2008. Bowdoin was indicted in the District’s federal court last year on charges of wire and securities fraud. He has pleaded not guilty. No trial date has been set.

Information for victims of the fraud can be obtained by calling 1-800-644-1535, prosecutors say.