The investigation into the assassination of North Korean dictator Kim Jong Un's half brother, Kim Jong Nam reads like a script from a bad Hollywood murder mystery. Now, one of the accused assassins claims that she thought the substance she put on Kim's face in the Malaysian International Airport was "baby oil." Authorities have identified the substance as VX nerve toxin - an incredibly poisonous compound that takes only a tiny amount to kill.

The incident took place at the airport on February 13 as Kim was preparing to board a flight to Macau. Kim told police that someone "grabbed or held his face from behind," after which he felt ill and went to the airport's medical dispensary. Within a few minutes, he slipped into unconciousness and died.

A CCTV camera caught the assassination on video:

Two people were arrested at the airport, including the "LOL lady" whose photo wearing the distinctive T-shirt went viral.

International experts were aghast at the use of VX to carry out an assassination:

Vestergaard pointed out the obvious risk posed by an assassin carrying a cloth with VX through an airport.

“We watched her walk across one of the terminals. She would have had to have carried this cloth with her. Even if she had gloves on, it would have dispersed somehow, somewhere,” she said. “Onto her, maybe onto someone else if she would have brushed against someone. If something would have dropped, onto a shoe, onto a suitcase.” Wherever she doused the cloth might be contaminated, Vestergaard added. “Even to open the vial and carry a vial” risks contaminating the environment.

The toxin “can remain on material, equipment and terrain for long periods,” the Organisation for the Prohibition of Chemical Weapons indicates on its website. “All nerve agents in pure state are colourless liquids. Their volatility varies widely. The consistency of VX may be likened to an involatile oil and is therefore classified as belonging to the group of persistent CW agents.” A suitcase sitting on the tarmac in the rain could have a drop of VX washed off, for example, but in other places it could linger for some time.

It works quickly. “Its effect is mainly through direct contact with the skin,” the OPCW indicates. Poisoning using a gas leads to a more rapid effect than through contact with the skin, because in the latter case it can take 20 to 30 minutes for the agent to reach deeper blood vessels. When it does, however, the effect is to essentially paralyze respiratory functions — the victim suffocates. Because persistent agents don’t evaporate, it requires a smaller amount to kill. In the case of VX, the OPCW says, the amount of the agent required to have a fatal effect in 50 percent of victims is 10 milligrams.

An amount the size of three snowflakes. One-ninth of a grain of sand.

“I think the investigation now — if this is confirmed to be nerve agent — is going to be massive because it is in an airport,” Vestergaard said. “You’re going to have to track those people that were in that area. What planes were being checked in. You have to have a hotline, if anyone gets sick. All those people will have to be tested.”

Incredibly, the Malaysian government made little effort to track passengers in the terminal at the time who may have been exposed, although they did sweep the airport and found no more contamination.

It is widely assumed that the North Korean government was behind the assassination. Four of the suspects in custody are North Korean citizens while the Malaysians are also seeking three other North Koreans - including a diplomat - who flew out of the airport on the same day as the assassination.

So the question arises: Why did the NoKo's use VX, a weapon of mass destruction, to kill a single person? It may very well be that the North Koreans are trying to send a message about the lengths they will go to get revenge on defectors. If so, the message was heard loud and clear.