Formerly a minister at the North Korean Embassy in London, Thae defected to South Korea last year.

The document quoted Thae as saying that the purged father, Ri Ung-gil, was the section chief for the European bureau at the International Department of the ruling party and had once been an Italian interpreter for former North Korean leaders Kim Il-sung and Kim Jong-il. "Ri himself, as well as his wife, son and grandson were all sent to political prisons." 

Ri's daughter-in-law, however, was excluded from the family purge mainly because her father Han is currently in a high-ranking position at the foreign ministry and her mother was from the family of Lim Chun-chu, one of North Korea's independence fighters, Thae was quoted as saying.

The document also showed that in December 2013, the month Jang was executed, the North Korean regime circulated a list of Jang and 15 other people convicted of treason among the country's foreign diplomatic missions and ordered them to remove the pictures or works of the listed people.   

The listed people's family members, including movie stars and several diplomats, were all sent to prison camps, he said.

The chief of the North Korea Strategy Center on Monday submitted documents of six high-ranking North Korean defectors' testimonies, including Thae, to the International Criminal Court in The Hague, calling for its investigation into Kim Jong-un. (Yonhap)