Defector warns of N Korea chemical threat - 24 Jul 09 [nLAhYUEwqJl]
While much of the world's attention has been on North Korea's nuclear weapons programme, a defector is warning of a more imminent threat. He says that Pyongyang has a sophisticated chemical and biological weapons programme - and that mentally disabled children are being used as human test subjects. Al Jazeera's Steve Chao reports.