It is the world's most deadly innervating agent and the United Nations has classified it as a weapon of mass destruction. Malaysian police confirmed on Friday that they found traces of Vx Gas on the body of Kim Jong-nam, assassinated on February 13 at Kuala Lumpur airport. The half-brother of the North Korean leader Kim Jong-un becomes the second known human victim of this poison, 100 times more toxic than sarin gas, and equally odorless and colorless.

Just 10 milligrams applied to the skin for the effect to be lethal.

This gas, whose complete scientific name is S-2 Diisoprophylaminoethyl methylphosphonothiolate attacks very quickly the nervous system and causes nausea, convulsions, loss of consciousness, and then death by asphyxia. It is necessary to use several antidotes at once in a very short period of time to hopefully save a person exposed to a fatal dose of this innervating agent.

Six thousand sheep killed

In March 1968, while the U.S Army was testing its biological and chemical weapons in the Skull Valley (Utah Skull Valley), some of this deadly gas accidentally spilled into a field, killing nearly 6,000 Sheep. This innervating agent is also suspected of being the cause of the accidental poisoning of twenty soldiers on the American base of Okinawa in 1969.

In the same year, under pressure from the public, U.S President Richard Nixon decided to ban chemical warfare use and research. However, the VX has not disappeared from the Earth's surface, and the United States has retained some stock. The other country to possess it officially is Russia which developed - Cold War obligates - its own version of this powerful poison called "Russian VX".

The terror of the Aum Sect

The only known precedent in the murder of Kim Jong-nam is the assassination of a Japanese man in the street by a member of the Aum sect in 1994. The victim - a 28-year-old man - was named a spy and sentenced to death by the sect's guru, Shoko Asahara.

The production of this deadly poison requires working in a sophisticated laboratory with highly toxic products, which is not within everyone's reach.