"Kim Jong-nam had been the biggest obstacle for Chairman Kim's pursuit of long-term power in North Korean society, [which is] heavily influenced by Confucian culture", he said.
On Wednesday, Kim's son Han Sol appeared in a video lasting 40 seconds posted on the website of a little known group called Cheollima Civil Defense, which appears to be involved in encouraging defections from North Korea.
North Korea's failure to apologise over its accusations against Malaysia over the Jong-nam murder investigation led to Malaysia's expelling of North Korea's ambassador.
Police Inspector-General Khalid Abu Bakar cited a need to protect witnesses as he announced the official verification of the dead man's identity, whose North Korean diplomatic passport bore the name Kim Chol.
South Koreans watch a television news showing a video footage of a man who claims he is Kim Han Sol, a nephew of North Korea's leader Kim Jong Un, at a railway station in Seoul on March 8, 2017. "The unnamed fourth government mentioned by Cheollima Civil Defense may be South Korea".
"Cheollima" is a mythical winged horse originating in ancient Chinese myths.
South Korea and the United States are accusing Pyongyang of ordering the hit on Kim.
It said the organisation responded last month to an emergency request by Kim Jong-nam's family members for "extraction and protection".
"We regret that several nations refused assistance to this family in this particular apolitical, humanitarian emergency".
It also thanked Lody Embrechts, the Dutch ambassador to North and South Korea, though Mr. Embrechts himself declined to comment on the situation.
A senior South Korean government official told NBC News that the country's "National Intelligence Service confirmed that the person on the YouTube [video] is Kim Han Sol".
Relations between both the countries soured over the probe into the February 13 murder of Kim, the estranged half-brother of North Korean leader Kim Jong Un.
In the video, he spoke ideal English with a faint British accent. A couple of years later he had enrolled at the Le Havre campus of France's prestigious Sciences Po (Paris Institute of Political Studies). They included three diplomats and six family members.
According to two individuals who studied with Han Sol, concerns over his safety date back years, however.
"At a time the government is continuing efforts to bring back Malaysians that are now blocked by North Korea, I wish to propose to all Malaysians including government and opposition leaders to unite to give full support towards all efforts that are being taken to solve this problem", he said in a speech uploaded on his official blog.