Security Gaps in Student Visa Program

The U.S. Department of Homeland Security is struggling to track down more than 6,000 foreign nationals who overstayed their student visas and have not been located since, ABC News reported.

"My greatest concern is that they could be doing anything," an Immigration and Customs Enforcement official told ABC. "Some of them could be here to do us harm."

The broadcaster also reported on the problem of visa fraud and of loose standards for institutions seeking certification to host international students.