More than 100 North Koreans have gone missing after being caught by secret police while trying to defect from the isolated country or even for trying to call relatives in South Korea, a Seoul-based human rights group said Thursday.

The Transitional Justice Working Group (TJWG) released a report detailing patterns of enforced disappearances identified through a study based on interviews with 62 North Korean escapees in South Korea.

Tens of thousands of North Koreans have defected in the decades since the Korean War ended in 1953 with an armistice, with many of those caught or repatriated sent to prison camps or other detention facilities before being released.