According to South Korea’s JoongAng Ilbo (English: The Central Times), China arrested two North Korean agents who attempted to murder Kim Han-sol, son of Kim Yong-nam. Kim Yong-nam was Kim Jong-un’s elder brother. North Koreans murdered him in Malaysia in February.
Seven members of North Korea’s intelligence agency tried to carry out the murder plan against Kim Han-sol. China tightened its security control during the 19th National Communist Party Congress, which helped the discovery of this attempt.
Source: DW News, October 30, 2017