leader, kim jong-un. something the country condemns as an act of war. >> u.s. law enforcement sources tell cnn the strong suspicion is that the reclusive country is the instigator of the hack and possibly outsourced it to a group elsewhere. as retaliation for the controversial film. the fbi is scrubbing sony's computer system, trying to gather enough evidence to be able to definitively point the finger at the hacking culprit. >> it is a complex, nuanced investigation. the more sophisticated hackers have gone through multiple, multiple infrastructures to get to where they've gotten to. so it's not something that sony is going to solve in a day or a week or a month. >> and sources tell us that the hackers had access to the sony computer system for several months before the fbi was brought in in november. so a lot of damage was done in that timeframe. making it harder for investigators to get to the bottom of it. and alisyn and chris, you may be wondering why the u.s. government isn't speaking out more. they want to be certain who the