Dozens of native-speaking English teachers and professors have been detained for distributing marijuana or taking the drug, police said Wednesday.

“Some of them taught students while intoxicated,” said the police. “The suspects included Americans, Canadians and other nationalities. And there were some Korean-Americans.”

Among them were three professors working at a college in Suwon, Gyeonggi Province, two English teachers at elementary schools in Cheonan, South Chungcheong Province, and Suwon and 22 teachers at private language institutes in the Seoul metropolitan area.

In the most serious case, officers at the Seoul District Policy Agency suspect a foreign English teacher of teaching children at a preschool right after smoking marijuana.

“The drug was found in his car in June, which was parked in front of the preschool,” said one of the officers.

The police said they had indicted five major suspects and booked 32 foreigners without detention.

The Justice Ministry has recently introduced a newly developed drug-testing kit to strengthen drug monitoring of foreign language teachers.

Foreign nationals seeking an E-2 teaching visa to work at public schools or private language institutes have been required to undergo drug tests at hospitals designated by the immigration office since 2008.

By Kim Yon-se (kys@heraldcorp.com)