To an outsider, the University of Northern New Jersey looked like a respectable college. It had a professional website with details about tuition costs, admissions, graduate and undergraduate courses.

There was even a real building associated with it. It was in Cranford, about 15 miles outside New York City.

But the school was a fake, set up by US federal agents to uncover a visa fraud scam.

Here's what we know about it:

They were brokers, recruiters and employers, charged with conspiracy to commit visa fraud and to harbor foreigners for profit. Most of them are in the US legally and live in New York, New Jersey and California.

They worked with brokers, and undercover agents posing as university officials, to help them stay in the US on student visas or to obtain work visas. According to Muzaffar Chishti, director of the Migration Policy Institute at the New York University School of Law, it's possible that some of the students also participated in the fraud, but it could be hard to establish their intent.

These included Facebook, Apple, Morgan Stanley and even the US Army. Chishti says the students either had legitimate degrees from other universities or their employers failed to do complete background checks.

In 2011, Susan Xiao-Ping Su, who founded the Tri-Valley University in Northern California, was sentenced to 16 years in prison. There has been at least one other case involving a college with locations in New York and New Jersey.

Chishti thinks that it's possible the authorities got the idea from interviews they did with students caught up in other visa fraud cases. The defendants face court hearings and possibly prison terms.

From PRI's The World ©2016 PRI