This combination of file photos shows Kim Jong Nam, left, the estranged half-brother of North Korean leader Kim Jong Un, in Narita, Japan, on May 4, 2001, and North Korean leader Kim Jong Un on May 9, 2016, in Pyongyang. Speculation that Kim Jong Nam was killed by two young female agents at the busy Kuala Lumpur airport last week left even the most seasoned toxicology sleuths shaking their heads. If a chemical agent really was to blame, finding it may be the hardest part of all. (RSS/AP Photos/Shizuo Kambayashi, Wong Maye-E, File)
Kim Jong Nam, the estranged half-brother of North Korean leader Kim Jong Un
