suspected to be behind the computer attack on sony pictures, there are new indications kim jong-un's country may become even more aggressive and let's bring in brian todd working this part of the story. >> kim jong-un was supposed to be toned down in his aggression for the first three years of his leadership after his father's death. he quickly tossed that notion out the window. tonight we're coming out of that period of mourning and observers are worried that this menacing, erratic young leader will do something very dangerous. ♪ ♪ >> he's now unshackled, free to be more aggressive as he comes out of the traditional three-year period of mourning for his late father. kim jong-un was supposed to observe that period by being less aggressive and lying low, many argue he never waited. >> in addition to executing his uncle, he has purged anyone who can question his leadership or his authority. >> kim's brazenly killed his