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, according to Malaysian police.
In a statement released Friday from the inspector general of police, 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 Feb. 13 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 Kim's face and also avoid becoming ill themselves. It has also not been made public 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 before the latest police statement. "As additional information is provided to the media by the police, it seems more likely that a new or modified chemical or biological agent was utilized in the attack."
On Thursday, Malaysia's police chief said investigators want to question a North Korean embassy official about Kim Jong Nam's death, saying he should cooperate 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 foreign officer has got immunity so we have to follow protocol," Khalid told reporters. "If you have nothing to hide, you don't have to be afraid. You should cooperate."
Khalid acknowledged that Malaysia would not be able to question Hyon if the embassy exercises its immunity privileges.
North Korea's official, state-controlled media mentioned the case for the first time Thursday, saying Malaysia's investigation was full of "holes and contradictions" without acknowledging the victim was Kim Jong Nam.
The report from KCNA largely echoed past comments by North Korea's ambassador to Malaysia, but the publication of at least some news inside North Korea could be a sign of its concern over growing international speculation that Pyongyang dispatched a hit squad to kill Kim Jong Nam.
Long estranged from North Korea's leadership, Kim Jong Nam had lived outside the country for years, staying in Macau, Singapore and Malaysia.
The two suspected attackers, and Indonesian woman and a Vietnamese woman, are in custody.
The Associated Press contributed to this report.