Malaysia authorities have arrested four people - a Vietnamese woman, an Indonesian woman, a Malaysian man, and North Korean man - and are seeking four North Koreans suspects who left the country the same day Kim Jong-nam died.
Amid rising tensions, Malaysia has recalled its envoy from Pyongyang.
"This shows to the elites that if they want to defect. that North Korea maintains an intelligence presence in Malaysia".
Besides the two woman, several men-including a North Korean citizen-have been arrested in connection with his death. Last week, they said they would not release the body to North Korea until Kim's next-of-kin provide DNA samples to confirm it is Kim Jong-nam.
Kim Hyon Hui, who bombed a Korean Air jet in 1987 after being trained as a North Korean agent, told the Japanese newspaper in a written interview that it was unthinkable that the women received strict training.
Meanwhile, North Korean dictator Kim Jong Un appears to have further asserted his control following this week's assassination of his half brother Kim Jong Nam. Two women of Southeast Asian nationalities approached Kim and appeared to apply a liquid to his face and cover it with a cloth, authorities say.
Mr Kim, in his mid-40s, died shortly after the attack, en route to a hospital after suffering a seizure, Malaysian officials said.
South Korean and USA officials believe Jong Nam was killed by agents from the North.
North Korea's ambassador Kang Chol was summoned by the Malaysian foreign ministry on Monday after he accused police of acting in a "deceiving" manner and added that Malaysia was "concealing something".
He once told reporters that he felt like he "was living on borrowed time".
Jong Nam, seemingly unfazed, walks up to an airport worker to explain what happened.
Investigators are trying to shed light on a death that set off waves of speculation over whether North Korea dispatched a hit squad to kill a man known for his drinking, gambling and complicated family life.
Disneyland lover Kim Jong-nam was also an embarrassment to Kim Jong-un and in 2001 he attempted to enter Japan on a forged passport to visit the theme park.
"They are watching who's coming in and who's leaving the country", said Go Myong-hyun (pic), a research fellow from the Seoul-based Asan Institute for policy studies, in a discussion on Arirang TV, an worldwide English-language South Korean network.