Kim Han-sol, the half-nephew of North Korean leader Kim Jong-un, was reportedly taken into CIA custody after his father was assassinated in February 2017.
Suki Kim, a Korean-American writer, made the claim in a piece published in the U.S. weekly The New Yorker on Monday.
The story is reportedly based on the writer's interview with members of an anti-North Korea group called Free Joseon, or Cheollima Civil Defense.
The writer said that Kim Han-sol reached out to Adrian Hong Chang, the leader of the anti-Pyongyang group, in February 2017 to seek assistance to escape soon after his father, Kim Jong-nam, was assassinated in Kuala Lumpur International Airport.
The group reportedly claimed that Kim Han-sol wanted to win refugee status in the Netherlands after escaping from Macau, but he was taken to an undisclosed location after a meeting with CIA agents. His whereabouts are still unknown.