A group of 20 musicians, including Kim's supposed former girlfriend Hyon Song Wol were executed by a firing squad for allegedly making pornographic videos, South Korea's Chosun Ilbo reported.
Media reports later alleged that Kim's wife, Ri Sol Ju, worked with the musicians before she married Kim.
On Sunday, the official Korean Central News Agency said that anyone who questioned North Korea's "highest dignity" would be "mercilessly" punished.
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