A federal grand jury has indicted officials at an English language school in Duluth on charges of illegally bringing female immigrants here to work as prostitutes in local Korean bars.

Dong Seok Yi, president and CEO of College Prep Academy, is accused of conspiring to enroll the immigrants at his school knowing they would not attend classes as required.

Federal prosecutors allege that Yi’s school issued them fraudulent federal documents, enabling them to stay in the U.S. The school’s academic coordinator, Sook An Kil, is accused of signing those documents and certifying the immigrants were attending classes when most never did.

The school claimed it had up to 100 students enrolled when less than half actually attended classes there, prosecutors said. Many instead began living and working in the country after obtaining student visas from the school.

Federal authorities said Yi and Chang Seon Song, the school’s academic director, referred the immigrants to another co-defendant, Sang Houn Kim, to get false documents that would support their student visa applications. Kim charged the immigrants thousands of dollars for those phony documents, prosecutors said.

A federal grand jury indicted the defendants on March 5 and returned a superseding indictment against them last week. The indictment charges one count of conspiracy and eight counts of making false statements in immigration documents. Federal agents searched the school Wednesday morning and seized bank accounts associated with it.

No one answered the telephone at the school Thursday morning. And officials at the school did not respond to an email request for comment.