Author Anna Fifield makes the claim about the North Korean leader's relative.
Kim Jong-nam death
An Indonesian woman accused of killing Kim Jong-nam tells the BBC she was shocked at being released.
Siti Aisyah had been accused of smearing a nerve agent on Mr Kim's face at Kuala Lumpur airport.
- Copyright: BBC
When Kim Jong-un took on the mantle of North Korea's supreme leadership, he had little political or military experience.
Rupert Wingfield-Hayes reports.
By Jonathan Head
BBC News, Bangkok