Kim Jong-Nam, the half-brother of North Korea's leader Kim Jong Un, was killed on February 13.
A few days later, the first North Korean to be arrested in connection with the case was a man carrying Malaysian documentation issued to foreign workers, which identified him as 46-year-old North Korean citizen Ri Jong Chol.
Malaysian detectives have also detained a 25-year-old Indonesian woman named Siti Aishah, her Malaysian boyfriend, and a woman carrying a Vietnamese passport identifying her as Doan Thi Huong, 28.
Kim Jong-Nam, the eldest son of Kim Jong Il, was once the favourite to assume the leadership of the hermit-state North Korea.
These are the key events in his life that led to his exile from North Korea and his death:
Kim Jong Nam is the exiled half brother of North Korean leader Kim Jong Un. Here he is pictured at Beijing airport in China in 2007.
He was the eldest son of Kim Jong Il and actress Song Hye Rim. From 1994 to 2001, he was considered the favourite to take over as the North Korean leader.
Here is the family tree.
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