Kim Jong-nam was given a very high amount of the toxic nerve agent VX and he died in pain within 15-20 minutes, Malaysia’s health minister says.
No antidote would have worked, said Subramaniam Sathasivam.
The half-brother of North Korea’s leader Kim Jong-un died two weeks ago after two women accosted him in a check-in hall at Kuala Lumpur International Airport.
The women say they thought they were doing a TV prank. North Korea denies killing the high-profile critic of the regime.
VX is classified as a weapon of mass destruction by the UN. A drop on the skin can kill in minutes.
One of two women held, Siti Aisyah, a 25-year-old Indonesian national, told officials from her country’s embassy that she was given 400 Malaysian ringgit ($90) to smear Kim Jong-nam’s face with “baby oil” as part of a reality show joke.
Doan Thi Huong, a 28-year-old Vietnamese national, has also said she thought she was taking part in a TV prank.
Malaysian police say the attackers had been trained to wash their hands immediately after the attack.
Some experts have suggested that they might have each smeared two different non-lethal elements of VX, which became deadly when mixed on Kim Jong-nam’s face.
A North Korean man has also been arrested in connection with the killing.
At least seven other suspects are wanted for questioning by police, including 44-year-old Hyon Kwang Song, second secretary at the North Korean embassy in Kuala Lumpur.
On February 26, Malaysian authorities swept the airport and declared it safe.
They are also analyzing samples found at a flat said to have been rented by suspects.