SUNNYVALE -- Striking a blow at a Silicon Valley school that attracted foreigners with student visas, federal agents on Thursday raided Sunnyvale's Herguan University and charged its CEO with visa fraud.

The indictment marks the second time federal officials have ensnared a Bay Area university in a growing effort to catch up with schools that allegedly rake in millions of dollars as so-called visa mills.

Herguan University leader Jerry Wang, 32, was arrested Thursday at his home in Santa Clara and charged in a 15-count indictment that could send him to prison for up to 23 years and amount to more than $1 million in fines.

The charges come a year after an investigation by this newspaper found Herguan was among a group of Bay Area schools -- including Pleasanton's now-shuttered Tri-Valley University -- that misrepresented information on federal applications, which allowed them to sponsor overseas students for coveted visas.

In the case of Tri-Valley, federal agents allege the unaccredited school had been paid millions of dollars by foreigners to obtain student visas that authorized them to remain in the U.S.

Thursday's indictment said Wang and others at Herguan submitted false documents, false transfer letters and made false statements to federal regulators.

Until last year, the school's lobby was decorated with photos of Wang with former Gov. Arnold Schwarzenegger and commendations from U.S. Rep. Mike Honda, D-San Jose, among others. The case could throw into question the immigration status for about 450 students enrolled at Herguan, most natives of India.

"We actually don't know what is happening at all," said one student who would only give his first name as Rai.

Last year, dozens of students at Tri-Valley University faced deportation threats and similar questions when federal agents raided the unaccredited school and charged its president, Susan Su, with raking in millions of dollars in a major visa scam.

Federal investigators found more than 550 students enrolled in the Alameda County university were registered as living at the same address: a two-bedroom apartment on El Camino Real in Sunnyvale.

The Tri-Valley scandal led U.S. Sen. Dianne Feinstein and others to call for a crackdown on similar schools, and a recent GAO report said Tri-Valley may be the tip of the iceberg.

On Thursday, attorneys in the Tri-Valley case requested that Su's trial date be delayed until April, after prosecutors discovered 1,500 new reports related to the case.

Su was indicted in April of 2011 on 35 counts, including conspiracy to commit visa fraud, wire fraud, mail fraud, money laundering, alien harboring and making false statements.

Wang is also CEO of the University of East-West Medicine, which shares a newly renovated two-story office building on Lawrence Expressway with Herguan University. The indictment didn't specifically allege problems at the other school.

"All we know is that Homeland Security showed up unannounced this afternoon," said Richard Friberg, vice president of University of East-West Medicine, who denied any knowledge of the alleged fraud. He said agents looked for images on computers and took copies of files.

Herguan now faces the loss of its authorization to enroll foreign students under the U.S. Department of Homeland Security's Student and Exchange Visitor Program. The U.S. Immigration and Customs Enforcement has taken the first step to revoke its certification; the university has 30 days to contest the action.

Herguan was closed Thursday but Friberg said it would reopen Friday. Students may continue to attend classes so long as the school stays certified.

But if it closes, they must try to immediately enroll in an accredited school to maintain their legal status -- or go home, empty-handed, after spending thousands of dollars toward what they hoped would be an American degree.

The school, which offers computer science and business degrees, was granted federal approval in 2008 to accept foreign students. The newspaper's 2011 investigation showed Herguan sent letters to immigration authorities from three accredited colleges, including Silicon Valley University and Northwestern Polytechnic University, promising to accept Herguan's credits. But representatives from those schools told this newspaper last year that they did not write such letters.

The indictment charges Wang with four counts of visa fraud, four false document counts, two counts of aggravated identify theft and one count of unauthorized access to a government computer.

One graduate still connected to Herguan, who only gave his name as Rajiv, told the newspaper Thursday that the news of the raid came as a shock.

He said foreign students were told if "that in the next 15 days, if something doesn't change, you either have to find a different school or leave the country."

Staff writer Robert Jordan contributed to this report.