The half-brother of North Korea's leader who was killed in a Kuala Lumpur airport more than a week ago had a nerve agent on his eye and his face.
A statement on Friday from the inspector general of police said that a preliminary analysis from the Chemistry Department of Malaysia identified the agent at "VX NERVE AGENT."
Kim Jong-nam, the half-brother of North Korean leader Kim Jong-un, died last week shortly after two women put a substance on his face while he was checking in for a flight.
Police have not said how the women were able to apply the nerve agent to his face and also avoid becoming ill themselves. It is not known if they were wearing some sort of thin gloves or if washing their hands quickly removed the danger.
Police had said earlier that the two attackers rubbed a liquid on Kim Jong-nam's face before walking away and quickly washing their hands. He sought help from airport staff but died before he reached the hospital.
The seeming contradiction of a poison that could kill him quickly but not sicken the attackers has stumped outside experts.
Bruce Goldberger, a leading toxicologist who heads the forensic medicine division at the University of Florida, said some protective measures must have been in place if the women handled the substance without gloves.
"It's also possible that the toxin was encapsulated, then activated when applied to the skin," he said.
Malaysia's police chief said on Thursday that investigators want to question a North Korean embassy official about Kim Jong-nam's death, saying he should co-operate if he has nothing to hide despite having diplomatic immunity.
Inspector-General of Police Khalid Abu Bakar said police have also asked Interpol to issue an alert for four North Korean men who left Malaysia the same day Kim Jong-nam was attacked by the two women.
The four men are believed to be back in North Korea, but police also want to question three other people still in Malaysia, including Hyon Kwang Song, a second secretary at the North Korean Embassy.
The two suspected attackers, and Indonesian woman and a Vietnamese woman, are in custody.