Federal agents said they have uncovered a massive international identity-theft scheme that victimized at least hundreds and maybe thousands of people, including an actress who appeared in the television shows Smallville and Supergirl.

On Thursday, federal authorities arrested two people in Virginia and two in Georgia who allegedly were part of a sophisticated operation that involved stealing identities and producing fake shell companies that could apply for high-balance credit cards.

The sprawling conspiracy involved many millions of dollars, authorities say, although after two years of investigating, they believe they have just scratched the surface. Court documents say the group would bill credit card companies for payments to its own shell companies, then route the money through various entities and sometimes out of the country.

Organized under the umbrella โ€œthe Deutche Group,โ€ the conspiracy allegedly involved people in India, Thailand and Britain as well as in the United States. Prosecutors are asking anyone who may have been a victim to come forward and help illuminate the scope of the scheme.

The conspirators would advertise jobs for Deutche Group on Craigslist, according to authorities, and then steal the personal information applicants gave them.

They also set up online companies offering airfare and hotel deals, according to court filings, then pocketed the funds and used stolen credit cards to book trips. Some travelers were stranded partway through vacations when their itineraries were canceled by fraud alerts.

When such fraud alerts led credit card companies to challenge charges, the group used digitally created images of credit cards and passports to back up their spending, authorities say.

One such passport used an image of actress Laura Vandervoort taken from a scene in the television show V involving visas, authorities said.

An FBI agent who was a fan of Smallville immediately recognized Vandervoortโ€™s photo, authorities said, and the image helped authorities lock down a time frame for when the fake passport was created and illuminated some of the groupโ€™s digital maneuvering.

Vandervoort played Supergirl on Smallville and also plays a villain on the show Supergirl.

According to the charging documents, the group even set up its own bank in India and attempted to join the Visa network so they could approve their own fraudulent transactions. One Indian co-conspirator tried to hide the illegal funds by buying diamonds with stolen credit cards, according to prosecutors.

Amit Chaudhry, of Ashburn, was arrested Thursday. He is accused of being the mastermind behind the U.S. operations. According to prosecutors, his siblings and other relatives and associates in India helped steal identities and create shell corporations.

To date, prosecutors have identified 353 fake companies associated with the scheme.

Prosecutors say a New York woman, questioning charges to her credit card, first alerted them to the group, which they believe has been operating since at least 2012.

In court on Thursday, Chaudhry appeared bewildered and said he did not understand the charges against him.

โ€œI never transferred money,โ€ he said. โ€œI donโ€™t have any significant ties to India.โ€

An affidavit filed in U.S. District Court in Alexandria, Va., lists five aliases for Chaudhry, including โ€œJohn Kingโ€ and โ€œSachin Sinha.โ€

Jacqueline Green, of Woodbridge, Va., also was arrested Thursday and charged with wire fraud.

Green appears to have met Chaudhry through her employment with ActioNet, a government information-technology contractor.

According to prosecutors, Green would overbill or fraudulently bill her company for training provided by Chaudhryโ€™s firm.