North Korean leader Kim Jong Un’s half-brother, Kim Jong Nam, died within 20 minutes of coming in contact with a nerve agent that was smothered on his face earlier this month at the airport in Kuala Lumpur, Malaysia’s health minister said on Sunday. Kim Jong Nam died on Feb. 13 after two women allegedly rubbed VX nerve agent on his face. “VX only requires 10 milligrams to be absorbed into the system to be lethal, so I presume that the amount of dose that went in is more than that,” Subramaniam Sathasivam said at a news conference. “The doses were so high and it did it so fast and all over the body, so it would have affected his heart, it would have affected his lungs, it would have affected everything.” South Korea has blamed the killing on the north, which has denied involvement. Malaysian officials believe four North Korean men who left Malaysia the day Kim Jong Nam was killed provided the two women with the nerve agent, a banned substance under international law. One of the two women, an Indonesian, previously said she thought she was participating in a TV prank. She also said she was given $90 before rubbing the nerve agent on Kim Jong Nam’s face.