The U.S. government has indicted a Virginia couple for running an H-1B visa-for-sale scheme the government said generated about $20 million.

Raju Kosuri and Smriti Jharia of Ashburn, Va., along with four co-conspirators, were indicted last week by a federal grand jury in Alexandria, Va., according to the Department of Justice (DOJ).

The scheme involved, in part, setting up a network of shell companies and the filing of H-1B visas applications for non-existent job vacancies.

Workers were required to pay their own visa processing fees and were treated as hourly contractors, the DOJ alleged. Treating H-1B workers as hourly contractors is in violation of the program rules, the government said.

More than 800 H-1B visa petitions were submitted over a period of nearly 15 years, according to court documents.

The six people indicted in the case face prison time of anywhere from 10 to 30 years if convicted.

Neither Kosuri nor Jharia could be reached immediately for comment.

The H-1B program may be susceptible to fraud. In 2008, the U.S. Citizenship and Immigration Service reported that a review of 246 randomly selected petitions filed in 2005 and 2006 revealed a fraud rate of just over 13%.

The government's analysis found forged documents, fake degrees and shell companies with fake locations.

Jail time is a risk for people convicted of H-1B fraud, although it's difficult to know how many have actually been sent to prison for it. One H-1B fraud case that may involve a prison sentence is pending in Texas.

A U.S. District Court judge in Dallas is scheduled to consider sentencing, as early as this week, for brothers Atul Nanda and Jiten "Jay" Nanda, for visa fraud following a jury verdict last November. They face up to 20 years in prison for using the visa program to create an on-demand workforce, the government alleged.