The Seoul High Court dropped the case filed by the Lawyers for a Democratic Society, or Minbyun, in August last year, saying it does not fulfill the requirements to constitute a suit. The lower court gave the same ruling in March.
Minbyun started the litigation after the National Intelligence Service had repeatedly rejected its demand for one-on-one meetings with the 12 defectors to ascertain their free will.
The defectors, all women employees except for one male manager, escaped from a restaurant they had worked at in Ningbo, China, before arriving in Seoul.
Pyongyang has urged Seoul to send them back to the North, claiming they were coaxed into moving to the South.
Minbyun questioned whether the defection came of their own will, calling for the need to confirm it through hearing from them firsthand. The spy agency said the defectors did not want to meet the lawyers.
It also raised doubts over the agency's equivocal attitude toward their settlements. The NIS later said they never underwent the state-run resettlement program like all other defectors, for protection as it's a very high-profile defection.
Usually, North Korean defectors receive three months of resettlement education at the Hanawon facility after coming to South Korea. According to the NIS, the defectors have all resettled in the country and many of them have entered a college to study.
The lawyers' group has reportedly requested the Ministry of Unification to confirm whether their defection was voluntary.
Minbyun filed a separate suit requesting custody protection for the defectors, which was turned down eventually by the top court in early March. (Yonhap)