More international students who said they were attending a university that was actually a shell created by the U.S. Department of Homeland Security (DHS) have been arrested in Michigan on immigration charges in recent months.

DHS and U.S. Immigration and Customs Enforcement (ICE) created the University of Farmington to expose weaknesses in the student visa immigration process, Assistant U.S. Attorney Brandon Helms wrote in a sentencing memo, as reported by the Detroit Free Press. The paper broke the story last spring.

“While ‘enrolled’ at the university, 100 percent of the foreign citizen students never spent a single second in a classroom. If it were truly about obtaining an education, the university would not have been able to attract anyone, because it had no teachers, classes or educational services,” the memo said.

While the students were granted student visas to enter the U.S., they were in violation when they did not actually attend the school, federal agencies said. Of about 250 people arrested, more than 200 students voluntarily left the U.S., and 50 stayed until being arrested or deported, the Free Press reported. ICE officials said many of the students were from India.

The paper reported that some students — claiming they were entrapped by the U.S. government, which operated the fake university — hired attorneys to defend their right to stay.

It remains unclear what happened to the tuition and fees paid by the students. It cost approximately $12,000 to enroll in the fake school, the Free Press reported.

Last winter, eight people were arrested and indicted for conspiracy to commit visa fraud and harboring aliens for profit. Federal agencies said those charged helped at least 600 “foreign citizens to illegally remain, reenter and work in the United States and actively recruited them to enroll in a fraudulent school as part of a ‘pay to stay’ scheme.”

After conviction, the eight were sentenced to between 12 and 24 months. They face deportation after they serve their terms.