Kim Jong-nam, the estranged half brother of North Korean leader Kim Jong-un, was killed with the banned VX nerve agent at Kuala Lumpur International Airport on February 13, Malaysian police said. A preliminary toxicology analysis found VX on swabs from his eyes and face. Investigators said two women approached him in the check-in hall and wiped chemicals on his face as he waited for a flight to Macau, where he lived with his family. Kim sought help from airport staff, suffered convulsions and died on the way to a hospital.

VX is an exceptionally toxic, oily nerve agent that can enter the body through the skin, eyes, inhalation or ingestion. Even a minute amount can be fatal, and the substance can persist in the environment for days or longer. It is banned under the Chemical Weapons Convention, which North Korea has not signed. Police said one of the two women became ill and vomited after the attack. Toxicologists questioned how the suspects survived handling the agent, while police continued to investigate how it entered Malaysia.

The discovery raised concerns about possible contamination at the airport and other locations, including the ambulance and medical facilities. Authorities said they were decontaminating the airport and places visited by the suspects, although 11 days had passed since the attack. No passengers, airport workers or medical staff were reported to have fallen ill.

Malaysian authorities accused North Korean agents of involvement and detained several people, including the two women, one Vietnamese and one Indonesian. They also sought other North Koreans, including an embassy official. Police argued that one woman’s decision to wash her hands immediately afterward indicated she knew she had handled a toxin. Relatives and acquaintances of the women maintained that they had been deceived.

North Korea denied responsibility, criticized the post-mortem examination and accused Malaysia of fabricating evidence under South Korean influence. It blamed Malaysia for the death and did not acknowledge that the victim, who carried a passport in the name Kim Chol, was Kim Jong-nam. The dispute strained relations between the two countries and prompted Malaysia to warn the North Korean envoy against making further accusations.

Kim Jong-nam, the eldest son of former leader Kim Jong-il, had once been considered a possible successor but lived abroad after being passed over in favor of Kim Jong-un. He later criticized North Korea’s policies and dynastic succession. Outside estimates put North Korea’s chemical weapons stockpile at 2,500 to 5,000 metric tons, potentially including VX, and its annual production capacity at up to 4,500 metric tons in normal conditions.