South Korean authorities are investigating suspected operatives working for North Korea on Jeju Island and in Changwon, South Gyeongsang Province, who told each other to “swallow thumb drives” if they get caught, a vernacular newspaper reported Monday.

The purported spies, mostly in their 50s and 60s, received orders from Kim Myong-song, an agent of the Cultural Exchange Bureau of the North’s Workers’ Party of Korea, to engage in anti-US campaigns, “infiltrate” into the militant Korean Confederation of Trade Unions and organize rallies against President Yoon Suk Yeol, Chosun Ilbo reported.

Counterespionage authorities are currently investigating five people in the Changwon-Jinju area, and three more on Jeju Island, including a former leader of the Jeju branch of the leftist Progressive Party surnamed Kang, on charges of violating the National Security Act, according to the newspaper.

Although the suspects are refusing to issue statements, authorities have secured multiple articles of evidence, including written orders from Pyongyang, and found that they used encryption programs such as Steganography and Dyber Dvoke to receive orders and report their activities to the North, the Chosun Ilbo reported.

According to the newspaper, the group in Changwon-Jinju, where defense contractors are clustered, allegedly had contact with Kim in Southeast Asian countries including Cambodia dating to 2016.

The other group on Jeju Island, with Kang at the center, has also allegedly corresponded with Kim since 2017.

The Cultural Exchange Bureau under the North's Workers’ Party of Korea ran espionage operations in South Korea under different names spanning decades.

In September 2021, operatives in North Chungcheong Province were indicted for violating the National Security Act as they were found to have been receiving secret orders from North Korean bureau agents surnamed Cho and Lee since 2017.

Seoul’s National Intelligence Service is looking into whether there are similar underground organizations of operatives run by the bureau in other parts of South Korea.

Also on Monday, the Chosun Ilbo ran an interview of Kim Young-hwan, the 1980s “godfather” of Jusapa, a political faction within South Korea's student movements that supported the North Korean political ideology known as Juche, who is now a researcher at nonprofit group NKnet.

According to Kim, North Korea has not given up on its dream of communizing the Korean Peninsula, and has always used such underground organizations as an important means for its goal of overturning the South Korean government.

(sophie@heraldcorp.com)