How assassins likely killed Kim Jong Un's half brother with a weapon of mass destruction

Malaysian authorities said Friday that Kim Jong Un’s half brother was assassinated with a nerve agent called VX, which is classified by the United Nations as a weapon of mass destruction.

Two women allegedly used the odorless and tasteless nerve agent to attack Kim Jong Nam, the eldest son of former North Korean leader Kim Jong Il, at Kuala Lumpur airport almost two weeks ago. After results from the first autopsy on Kim Jong Nam proved inconclusive, a second round of testing revealed the presence of the highly-toxic chemical.

The North Korean government has not responded to the latest developments in the case but has previously said it would reject the findings of any autopsy, calling it a violation of the victim’s human rights.

Khalid Abu Bakar, Malaysia’s inspector general, told reporters on Friday that the findings came from swabs taken from the victim’s face and eyes. Because VX does not evaporate quickly and can remain toxic for some time, Khalid said the airport would be decontaminated.

Khalid revealed that an investigation is underway into how the nerve agent was brought into the country, but the substance — typically an oily, amber-colored liquid — is lethal at extremely low doses, meaning it could have easily been concealed for smuggling.

What is VX?

VX is the common name for ethyl N-2-Diisopropylaminoethyl Methylphosphonothiolate, a chemical weapon described by the CDC as “the most potent of all nerve agents.” It only takes about 5 milligrams of VX coming into contact with skin to kill an adult weighing 150 pounds (70 kilograms).

According to Malaysian authorities, Kim Jong Nam’s attackers likely doused their hands with the chemical and rubbed it on his face.

So why didn’t the attackers die?

Khalid said that one of the attackers suffered from vomiting and other symptoms associated with the toxin. He added that the VX nerve agent was placed on the hands of the female assassins by a North Korean man, who is also in police custody.

One possibility, according to Raymond Zilinskas, director of the chemical and biological nonproliferation program at the Middlebury Institute of International Studies, is that the two attackers could have each had one precursor to the nerve agent on their hands, which would combine to form VX when they touched the victim’s face.

Following the attack, the women were seen holding their hands away from their bodies and quickly going to a bathroom where they washed their hands. There’s also an antidote for VX that is relatively common and easy to obtain.

North Korea’s embassy in Malaysia claims the women are innocent and should be freed. If they really had poison on their hands, an embassy statement said, “then how is it possible that these female suspects could still be alive?”

How does VX work?

As with all nerve agents, VX prevents the proper operation of the acetylcholinesterase enzyme, which acts as the body’s “off switch” for glands and muscles. Without an “off switch,” the glands and muscles are constantly being stimulated. “They may tire and no longer be able to sustain breathing function,” the CDC says.

Some of the side effects of exposure to VX include convulsions, loss of consciousness, paralysis, and fatal respiratory failure.

Who created VX?

British scientists created VX while researching pesticides in the 1950s. It was eventually mass-produced as a chemical weapon and stockpiled by the U.S. during the Cold War.

Russia is the only other country which has admitted to having VX, but under the Chemical Weapons Convention of 1997, both countries had to destroy their stockpiles.

Countries are now allowed to possess limited samples of VX for research purposes, but North Korea is one of seven nations that has not agreed to the Chemical Weapons Convention. North Korea is estimated to have up to 5,000 metric tons of chemical weapons, according to the Nuclear Threat Initiative, mostly comprised of VX and the related nerve agent Sarin.

Has VX ever been used before?

There’s only been one other confirmed VX fatality. In 1994, the Japanese doomsday cult Aum Shinrikyo — known for the 1995 sarin gas attack in the Tokyo subway system — murdered an office worker in Osaka and attempted to murder two other people with VX.

Although there is no conclusive proof, some experts believe Saddam Hussein may have used VX during the Iran-Iraq war in the 1980s. The French Defense Ministry claims that VX is among a range of chemical weapons stockpiled by Syria. VX testing by the U.S. Army was also likely the cause of death for more than 6,000 sheep in Utah in 1964.

VX has also made its way into pop culture — the deadly nerve agent featured prominently in the 1996 blockbuster film The Rock starring Nicolas Cage and Sean Connery, where it appeared in the form of gas contained in menacing green orbs. In real life, pure VX is an odorless and colorless liquid, but impurities introduced during the manufacturing process typically gives it an orange or yellow hue.