Malaysian authorities said VX nerve agent was used to kill Kim Jong-nam, the estranged half-brother of North Korean leader Kim Jong-un, at Kuala Lumpur International Airport on February 13. Preliminary chemical analysis detected the banned substance in swabs from his eyes and face. Two women allegedly approached him in the departure hall and wiped chemicals onto his face as he prepared to travel to Macau, where he lived with his family. He sought medical help, suffered convulsions and died while being taken to hospital.

The finding intensified suspicions of North Korean involvement and deepened a diplomatic dispute. Malaysian investigators linked the attack to North Korean agents and sought several North Koreans, including an embassy official and an employee of the state airline, Air Koryo. Reports differed on the number detained, but those in custody included the Vietnamese and Indonesian women accused of carrying out the attack. Police said the women knew they were handling poison; relatives and acquaintances maintained they may have been deceived.

North Korea denied responsibility, accused Malaysia of fabricating evidence in cooperation with its enemies and blamed the Malaysian government for the death. Pyongyang referred to the victim as a North Korean citizen without acknowledging that he was Kim Jong-nam, who was travelling under the name Kim Chol. Malaysia defended its investigation and warned that North Korea’s ambassador could be expelled over his accusations. The confrontation strained previously accommodating relations between the two countries.

VX is an extremely potent, oily, largely odorless nerve agent that disrupts nerve signaling. Tiny quantities absorbed through the skin can be fatal, causing symptoms including vomiting, confusion, seizures and paralysis. It is banned under the 1993 Chemical Weapons Convention. Its identification raised questions about how the attackers handled it and how it entered Malaysia. Police reported that one female suspect experienced vomiting. Experts suggested that rapid washing or an antidote might explain the suspects’ survival, but these possibilities were unconfirmed.

The discovery also prompted concerns about contamination at the airport, which had remained open for roughly 11 days without decontamination. VX can persist on surfaces for days or longer, potentially exposing people at the airport, in the ambulance or at medical facilities. Authorities announced plans to inspect and decontaminate relevant areas. No illnesses were reported among other passengers, airport workers or medical personnel.

North Korea has not joined the Chemical Weapons Convention. Estimates cited in the reports placed its chemical weapons stockpile at 2,500–5,000 tonnes and annual production capacity at approximately 4,500 tonnes, potentially rising to 12,000 during a crisis. Its suspected arsenal includes mustard, phosgene, sarin and VX.

Kim Jong-nam, the eldest son of former leader Kim Jong-il, was once considered a possible successor. He fell from favor after being caught entering Japan on a false passport in 2001, subsequently lived abroad and became a critic of North Korea’s policies and hereditary succession. His killing brought renewed attention to the country’s suspected chemical weapons capabilities and history of overseas assassination operations.