North Korea may have found a new use for its large stockpile of chemical and biological weapons, which are meant to attack South Korean and U.S. troops in case of another war. Malaysian police said Friday that a chemical weapon – the toxic VX nerve agent – was used to kill the estranged half brother of Pyongyang’s absolute leader at the Kuala Lumpur airport on Feb. 13. If North Korea ‘s involvement is confirmed, this would be an unusual and extremely high-profile use of its chemicals in an assassination.