NEW : Taliban source : Mullah Omar has been killed in a drone strike. NEW : Law enforcement official : Threats to Bergdahl family came via e-mail . John Kerry says released Taliban figures will be monitored . If they turn to violent ways , they could die violent deaths , he says .
NEW : Taliban source : Bergdahl did not convert to Islam , learned to speak Pashto . NEW : Law enforcement official : Threats to Bergdahl family came via e-mail . John Kerry says released Taliban figures will be monitored . If they turn to violent ways , they could die violent deaths , he says .