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

VX is an extremely potent, persistent nerve agent that disrupts nerve signaling. A tiny amount absorbed through the skin can be fatal, causing symptoms including vomiting, seizures, paralysis and loss of consciousness. The oily, odorless substance is banned under the 1993 Chemical Weapons Convention. Its use in a busy airport raised concerns about contamination, particularly because authorities had gone approximately 11 days without decontaminating the premises. Police subsequently announced cleanup plans. No illnesses were reported among passengers, airport workers or medical staff, although police said one of the female suspects had vomited.

Investigators detained suspects including a Vietnamese woman, an Indonesian woman and a North Korean man, and sought several other North Koreans, including an embassy official and an employee of the state airline, Air Koryo. Malaysian police alleged that North Korean agents directed the attack and that the women knew they were handling a toxin. Relatives and acquaintances maintained that the women could have been deceived. Toxicologists questioned how they survived handling VX; police said they had been instructed to wash their hands afterward, while one expert suggested that antidotes might explain their survival. Authorities were also investigating how the substance entered Malaysia.

North Korea denied involvement and accused Malaysia of fabricating evidence under South Korean influence. It challenged the investigation and post-mortem examination, blamed Malaysia for the death and did not acknowledge the victim as Kim Jong-nam, whose passport bore the name Kim Chol. The dispute sharply strained relations between countries that had previously maintained relatively open travel ties. Malaysia’s foreign minister warned that North Korea’s ambassador could be expelled over his accusations.

Kim Jong-nam, the eldest son of former leader Kim Jong-il, had once been considered a possible successor. His prospects diminished 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 also renewed concern about North Korea’s chemical weapons capabilities. The country has not signed the Chemical Weapons Convention and was estimated to possess 2,500–5,000 metric tons of chemical agents, including VX. Reports put potential production at approximately 4,500 tons annually, rising to 12,000 during a crisis. Analysts warned that these capabilities could threaten South Korea and enable overseas attacks. The passages also recalled earlier VX attacks by Japan’s Aum Shinrikyo cult in 1994–95, which targeted three people and killed one.