The banned chemical weapon VX is considered by some experts to be the nastiest of the nasty nerve agents known to exist. With a consistency similar to motor oil, it lingers for long periods in the environment and even a tiny amount causes victims' bodies to flood with fluids, producing a feeling of drowning before death, reports the AP. So when Malaysian authorities announced Friday that VX was to blame for the Feb. 13 death of the North Korean leader's exiled half-brother inside a busy Kuala Lumpur airport, it raised nearly as many questions as answers, including how the two women who allegedly attacked Kim Jong Nam with it could have survived. A toxicologist says the woman shouldn't have escaped unscathed—one reportedly vomited—as police have said they did not wear gloves or protective gear and only washed their hands after the attack.
One theory is that they took an antidote in advance. And the New York Times points out VX becomes lethal when two chemicals are mixed, something that can be done "at the last moment." Police have said the two suspects rubbed something on Kim's face in quick succession. Another toxicologist notes that VX—a small amount of which could kill 500 people through skin exposure—would likely have come from a chemical weapons laboratory, making it more likely that the attack was executed by a government. But he wants an independent lab to verify that VX was used, given that no one else at the airport was sickened. On Friday officials announced the facility would be decontaminated. (Read more nerve agents stories.)