WSJ reports that Malaysian authorities announced that the substance that killed the half-brother of Kim Jong Un last week was the highly-restricted nerve agent VX, considered a weapon of mass destruction by the United Nations. While North Korea has denied any connection to the incident, they are one of the few countries on the planet that has not agreed to destroy its inventory of VX.

The worry: North Korea's brazen use of such a dangerous substance is a signal to the world regarding its chemical weapons stockpiles. As one researcher told the WSJ: "That suggests that the intelligence on North Korea's capabilities is likely dated and inaccurate. We don't have a shadow of a clue."