Kim Jong-nam, the estranged half-brother of North Korean leader Kim Jong-un, died after being attacked at Kuala Lumpur International Airport on February 13. Malaysian authorities said preliminary toxicology tests found VX nerve agent on his eyes and face. Two women approached him in the airport’s check-in hall and allegedly wiped chemicals on his face. He sought medical help, suffered convulsions and died on the way to hospital.

VX is a highly toxic, persistent nerve agent banned under the Chemical Weapons Convention. It can be absorbed through the skin and can kill in minute quantities. One of the accused women reportedly vomited after the attack. Toxicologists questioned how the women could handle the substance and leave the scene without more severe symptoms. Malaysian police said they were investigating how VX entered the country and were arranging to decontaminate the airport and other locations the suspects had visited. No passengers, airport workers or medical staff who treated Kim had reported becoming ill.

Malaysian investigators suspect North Korean involvement. Authorities detained the two women, one Vietnamese and one Indonesian, and sought several North Koreans, including an embassy official and an employee of the state-owned airline Air Koryo. Relatives of the women said they believed the pair had been deceived, while Malaysian police maintained that the attack was deliberate.

North Korea denied responsibility, accused Malaysia of fabricating evidence under South Korean influence and challenged its investigation and post-mortem examination. Pyongyang also blamed Malaysia for the death because it occurred on Malaysian territory, while declining to confirm that the victim was Kim Jong-nam. He had been travelling on a passport under the name Kim Chol. The dispute strained relations between the two countries, and Kim’s body remained in a hospital mortuary amid disagreement over who should claim it.

Kim Jong-nam was the eldest son of former North Korean leader Kim Jong-il and had once been considered a possible successor. He lived abroad for years after being passed over in favour of Kim Jong-un and became a prominent critic of the regime’s policies and dynastic succession.

North Korea has not signed the Chemical Weapons Convention and is widely believed to possess a large chemical weapons stockpile, including VX and other agents. Estimates cited in the reports put its inventory at 2,500 to 5,000 tonnes, with substantial production capacity. The killing renewed concern about the potential use of such weapons beyond the Korean Peninsula.