Malaysian authorities have performed an autopsy on the body, but did not give any results yet. North Korea has made no comment on the killing.
Kim Jong Nam, is, like his half-brother Kim Jong-Un, a son of Kim Jong Il, the previous leader of North Korea, but from a different mother.
Kim Jong-Nam fell from grace a long time ago.
“As the oldest son of Kim Jong-Il, in the 1990's, he was seen within the North Korean political apparatus as the likely successor to his father,” says John Nillson-Wright, a senior research fellow with the Asia program of Chatham House.
“He showed up unexpectedly in 2001 on a trip under an assumed name, false passport, trying to get into Japan, allegedly to make a trip to Disneyland. That effectively discredited him in the eyes of his father and he lost the right to take over his fathers' succession.”
Kim Jong-Nam then went into exile, and lived mainly in the Chinese enclave of Macau. But his life got even more complicated as a result of the matter of his uncle Jang Song-Thaek.
Jang was married to the only daughter of former North Korean supreme leader , the only sister of former North Korean supreme leader and the aunt of , the current.
At one point, Jang was thought to be the second most powerful man after Kim Jong Il. And he remained so after Kim Jong Il died in 2011.
But apparently Kim Jung Un thought he became too powerful and killed him, allegedly by an anti-aircraft gun three years ago.
Kim Jong-Nam wrote a letter to Kim Jong-Un, saying, please do not kill my family. But Kim Jong-Un ignored that letter.
Before his death, Jang Song-Thaek had become the person who sponsored Kim Jong-Nam, and continued to give him money after he went abroad.
So when he died, Kim Jong-Nam’s money source dried up, and he was thought to have established a company to make up for the losses.
“Kim Jong-Nam was eliminated from the whole family territory of Kim Il-Song,” says Noh Jonsun, an emeritus professor with Yonsei University in Seoul.
“He grew up in the house of Jang Song-Thaek. And when Jang Song-Thaek was eliminated, he could not give money to Kim Jong-Nam anymore, and so Kim Jong-Nam had to survive through his own business.”
The nature of the business that was established in either “Singapore or Malaysia” is not clear, but Noh Jonsun thinks it may have involved arms- or drugs trade.
The timing of the killing may not have been a coincidence, says Noh.
“Kim Jong-Un's supporters like to show their loyalty to Kim Jong-Un. [The killing coincides with] the 75th anniversary of the birth of Kim Jong-Il on February 16th.
“Followers may have wanted to give some big gift to Kim Jong-Un, to make him happy,” he says.
According to South Korean intelligence information that was published this week, there have been more attempts on his life before, and Noh Jonsun says that Kim Jong-Un issued the order to kill his half-brother five years ago. And also that Kim Jong-Nam pleaded for his life.
“Kim Jong-Nam wrote a letter to Kim Jong-Un, saying, please do not kill my family. The only way to survive is your forgiveness to me and the members of my family. Otherwise the [only way left] is to commit suicide. So please do not kill my family.
“But Kim Jong-Un ignored that letter.
Meanwhile, if the killing is indeed an act sponsored by Pyongyang, it would fit into a tradition of state-sanctioned assassinations.
“The North Korean state has a long history of organizing lethal activities,” says Nillson-Wright, describing the raid on the Blue House, the presidential residence in South Korea, in 1968; a failed bomb attack on president Park in the Seventies.
In 1983 North Korean agents were able to assassinate two thirds of the South Korean cabinet which was then on a visit to Myanmar, and there was the attack on Korean Air flight 858 in 1987 which exploded after a bomb, planted by North Korean operatives went off, killing all 104 passengers and 11 crew.
Apart from these major attacks, “there have been many cases in which individual opponents of the North Korean government have been targeted either in South Korea, or in Europe or in Asia as we see in this recent attack,” according to Nillson-Wright.