http://www.slate.com/articles/news_and_politics/foreigners/2015/01/north_korea_s_decades_of_human_rights_abuses_pyongyang_s_attack_on_sony.html

In the 1990s, a large group of prisoners were released from North Korea’s secret labor camps. These were not criminals, nor were they even political enemies. On the contrary, they were, in the words of a defector, the grandchildren and even great-grandchildren of “landlords, capitalists, collaborators with the Japanese colonial government, and other people with bad family background.” The Soviet Union once arrested the wives and children of political prisoners, and Russia recently sent the brother of a dissident politician to prison. But North Korea kept generations of families living in camps for decades on end.