The North Korean leader's half brother was killed by VX, a lethal nerve agent that can be absorbed through the skin, Malaysian police said Friday, giving their first assessment of the cause of Kim Jong Nam's death.
The finding will add to the increasing pile of evidence suggesting that Kim Jong Un's regime in North Korea was behind the brazen and public attack on Kim Jong Nam in a Kuala Lumpur airport terminal last week.
"The chemical substance on the exhibits has been identified as. . . VX nerve agent," Khalid Abu Bakar, Malaysia's inspector general of police, said in a statement Friday after the Center for Chemical Weapons Analysis analysed swabs from the man's face and eyes.
VX is the one of the most toxic and fastest acting chemical warfare agents, much more toxic than sarin, and especially so if entry is through the skin, according to the U.S.
Centers for Disease Control and Prevention.
"Symptoms will appear within a few seconds after exposure to the vapour form of VX, and within a few minutes to up to 18 hours after exposure to the liquid form," the CDC says on its website.
"It is possible that any visible VX liquid contact on the skin, unless washed off immediately, would be lethal," the CDC says.
Exposure to a large dose of VX can cause convulsions, a loss of consciousness and respiratory failure possibly leading to death, the CDC says.
Two women attacked Kim Jong Nam at the airport, smearing a cream on his face. He immediately sought help and was taken to the airport medical clinic, where leaked photos showed him slumped in a chair with his eyes closed. He reportedly suffered seizures then died in an ambulance on his way to hospital.
The man-made nerve agent is classified as a chemical weapon and is thought to be one of those stockpiled by Bashar al-Assad's regime in Syria until it agreed to get rid of its chemical weapons in 2014.
VX is also believed to have been used by Saddam Hussein on Kurds during the final days of the Iran-Iraq war.
South Korean authorities have accused Kim Jong Un, who came to power in North Korea in 2011, of putting out a "standing order" to assassinate his older half brother.
This would fit with Kim Jong Un's track record of getting rid of potential rivals to his power. He had his uncle, Jang Song Thaek, executed at the end of 2013 for apparently amassing his own power base. Jang was a mentor to Kim Jong Nam, who had previously been considered a potential leader in the three-generation Communist dynasty.
North Korea had strongly objected to Malaysia conducting an autopsy on the man's body, saying that he carried a diplomatic passport and therefore was not subject to under local laws.
The North Korean ambassador in Kuala Lumpur has read out several angry statements, accusing Malaysia of trying to "besmirch" Pyongyang's reputation and of being put up to this by the South Korean government. This was reiterated in a virulent 763-word statement published by the North's state news agency.
There were also reports that of an attempted break-in at the hospital morgue where Kim Jong Nam's body is being held.
But the Kuala Lumpur government, one of the few in the world that has friendly relations with Pyongyang, has remained adamant that it will follow all procedures required when a suspicious death occurs on its soil.
It has named eight North Koreans, including one diplomat, who it considers suspects in the attack. One, a scientist who had been living in Kuala Lumpur for a year, is in custody but three others are at large in Malaysia.
The other four left Malaysia on the day of the attack, taking a circuitous route - via Dubai and Vladivostok - to get back to Pyongyang without going through China.
The Chinese government had been protecting Kim Jong Nam and was widely thought to consider him a potential replacement for Kim Jong Un if he became intolerably hostile to Beijing.