Malaysian authorities say initial autopsy results show a chemical weapon — VX nerve agent — was used in the fatal poisoning of Kim Jong Nam, older half-brother of North Korea's leader Kim Jong Un.VX is an odorless substance that can exist as liquid or gas. It can kill within minutes if it's passed through the skin. It is 10 times more toxic than sarin and classified as a weapon of mass destruction.Early last week, while Kim Jong Nam was traveling through the Kuala Lumpur International Airport, two women approached him, touched his face and held a cloth over it. He was able to walk to a help desk, which took him to an airport nurse area, but soon fell severely ill and died before making it to the hospital.The women who approached him were caught on airport security cameras and captured within days of the attack. They are from Southeast Asian countries and are now in custody. But police believe the plot involved far more people than the two women. It's seekingat least seven North Koreans, including a diplomat, in connection with the crime.That VX nerve agent is responsible for Kim's death strengthens the claims made by South Korea that the North Korean regime ordered the hit. VX is man-made and not that difficult to produce, according to chemical weapons experts. But it tends to be used by state actors. For example, Saddam Hussein is believed to have used VX nerve agent on Kurdish citizens of Iraq in the 1980s.South Korea last week blamed North Korea for the killing and called the rather public assassination a terrorist act. North Korean officials in Malaysia, meanwhile, were rejecting the autopsy's results before it was even concluded. And to add to all this drama, someone this week apparently tried to break into the morgue where Kim's body is being held. That incident is under investigation.The body believed to be that of Kim Jong Nam has yet to be identified by next of kin, so Malaysia is refusing to release the remains. Malaysian authorities have asked the North Koreans to provide a DNA sample from a Kim family member. But North Korea is not cooperating.The Malaysian police inspector general has been talking with the press this week, but not answering many questions, saying instead that a lot of answers reporters are seeking are "subjects of the investigation." Later he said that the investigation could last years.Chan Kok Leong contributed to this post, from Kuala Lumpur. Copyright 2017 NPR. To see more, visit http://www.npr.org/.