"They expect the search to take the remainder of today," said James Cybert, HotMovies director of business development.
Cybert cynically characterized the raid as a "beautiful day in the neighborhood" on Facebook.
The FBI agents were armed with search warrants and more than 100 employees were detained and later released.
FBI spokesman J.J. Klaver told XBIZ that agents are still at the company's offices in Philadelphia.
"No one is in custody," Klaver said. "There have been no [federal] indictments filed."
Klaver would provide no other details. Philadelphia police told XBIZ that the raid was orchestrated by the FBI.
It's the second raid performed on an online adult company this year by federal authorities.
Earlier this year, federal prosecutors raided the offices of Pittsburgh-based Right Ascension, which operates AdultDVDEmpire.com. The company was indicted on obscenity charges after mailing four DVDs containing material deemed obscene to an Erie, Pa., post office box in May 2007.
Right Ascension eventually paid a $75,000 fine and was placed on two years’ probation.
National A-1, which uses MovieDollars.com as the hub for its affiliate program, operates scores of adult websites, including Clips.com, FetishMovies.com, HotMoviesForHer.com, BigBreasts.com, BDSMvod.com, ClassicVOD.com, CuckoldsVOD.com, GayHotClips.com, FetishClips.com, HentaiVOD.com, HomeGrownVOD.com, JapanHotMovies.com, TVTSvod.com, Perverts.com, RealLesbianVOD.com, GayHotMovies.com, GayMovies.com, Spanking.com, TabooVOD.com, Torture.com, VintageMovies.com, VODAfterDark.com, AVNVOD.com, CoedsVOD.com, GroobyVOD.com, ElegantAngelVOD.com, EdPowersVOD.com, BuckAngelVOD.com, Channel69.com, ExtremeVOD.com, HomeGrownVOD.com, NettlesVOD.com, RascalVOD.com, VideoXPixVOD.com.
VOD.com and IndependentVOD.com, as well as HotMovies.com. The company also owns and operates numerous mainstream sites.
Parent company National A-1 Advertising's sites, including HotMovies.com, were down for most of the day, but as of 4 p.m. (PST) the sites are back up.