Malaysian police said preliminary tests found VX nerve agent on the eyes and face of Kim Jong-nam, the estranged half brother of North Korean leader Kim Jong-un, following his fatal poisoning at Kuala Lumpur’s airport on February 13. Two women allegedly wiped chemicals across his face as he waited for a flight to Macau, where he lived with his family. He sought medical assistance, suffered convulsions and died while being transported to hospital. He was travelling under the name Kim Chol; Malaysian authorities identified him as Kim Jong-nam, but North Korea had not acknowledged that identity.

VX is an extremely potent chemical weapon banned under the 1993 Chemical Weapons Convention. A tiny amount absorbed through the skin can disrupt the nervous system and cause fatal seizures and paralysis. Its oily consistency allows it to remain dangerous for days or weeks, raising concerns about contamination at the airport, in the ambulance and at medical facilities. Authorities announced decontamination efforts roughly 11 days after the attack, during which tens of thousands of passengers had passed through the airport. No passengers, airport employees or medical staff were reported ill.

Police said one of the two suspected attackers, a Vietnamese woman and an Indonesian woman, vomited after the incident. Investigators argued that their immediate handwashing indicated awareness that they had handled poison. Relatives and acquaintances maintained that the women may have been deceived into participating. Toxicologists questioned how they avoided more severe poisoning, with one suggesting possible antidote use; that explanation remained speculative. Police were also investigating how VX entered Malaysia.

Malaysian investigators linked the attack to North Korean agents and sought several North Koreans, including a senior embassy official and an employee of state airline Air Koryo. The reports gave differing custody totals of three or four people. North Korea denied involvement, accused Malaysia of fabricating evidence in cooperation with South Korea and challenged the post-mortem examination. A statement attributed to North Korea’s Jurists Committee blamed Malaysia because the death occurred there and invoked Pyongyang’s status as a nuclear weapons state. Malaysia’s foreign minister warned that the North Korean ambassador could be expelled over his accusations. A dispute over custody of the body further strained relations between countries that had previously maintained relatively accessible travel and business ties.

Kim Jong-nam, the eldest son of former leader Kim Jong-il, had once been considered a potential successor. His prospects reportedly faded after he was caught entering Japan on a false passport in 2001. He subsequently lived abroad and publicly criticized North Korea’s policies and hereditary succession.

The killing renewed scrutiny of North Korea’s suspected chemical weapons program. The country has not signed the Chemical Weapons Convention, and outside estimates place its stockpile at 2,500–5,000 tons, with production capacity potentially rising from 4,500 tons annually to 12,000 during a crisis. Suspected agents include mustard, phosgene, sarin and VX. Analysts have warned about their possible use against South Korea or in covert operations abroad. VX has rarely been used in assassinations; Japan’s Aum Shinrikyo cult attacked three people with homemade VX in 1994–95, killing one.