Kim Jong Nam died after reportedly being attacked by two women believed to be North Korean agents at a Kuala Lumpur airport on Monday.
Jong Nam, the eldest son of the late former leader Kim Jong Il, was once seen as heir apparent but fell out of favour following an embarrassing botched bid in 2001 to enter Japan on a forged passport and visit Disneyland.
He has since lived in virtual exile, mainly in the Chinese territory of Macau, while Jong Un took over the isolated, nuclear-armed state after the death of his father in December 2011.
The North in 2012 tried to assassinate Jong Nam – known as a supporter of reform in Pyongyang – Seoul lawmakers said, following a closed-door briefing by the chief of the National Intelligence Service, Lee Byung-Ho.
“According to (Lee)… there was one (assassination) bid in 2012, and Jong Nam in April 2012 sent a letter to Jong Un saying ‘Please spare me and my family,'” Kim Byung-Kee, a member of the parliamentary intelligence committee, told reporters.
“It also said ‘We have nowhere to go… we know that the only way to escape is suicide’,” he said, adding Jong Nam had little political support at home and posed little threat to Jong Un.
Jong Nam’s family – his former and current wives and three children – are currently living in Beijing and Macau, said another committee member, Lee Cheol-Woo.
“They are under the protection by the Chinese authorities,” he said, adding that Jong Nam had entered Malaysia on Feb 6, a week before his death.
Jong Nam’s murder is the highest profile death under Kim Jong Un’s regime since the execution of the leader’s uncle, Jang Song Thaek, in December 2013.
Jang, known to be close to China and an advocate of economic reform in the North, was charged with treason.
Jong Nam, believed to have ties with Beijing’s elite, was a relatively outspoken figure, publicly criticising Pyongyang’s political system.
The 45-year-old said he “personally opposed” the hereditary power transfer in his own family, during an interview with Japan’s Asahi TV in 2010.
One of his sons – Han-Sol – also described his uncle, Jong Un, as a “dictator” in a rare interview with a Finnish TV station in 2012 while he was studying in Europe.