inside access. >> u.s. investigators have evidence that hackers stole the computer credentials of a sony system administrator to get inside access. but could another government helped north korea? u.s. says there are signs others other involved. >> signs suggest iran is involved. they have worked together on missile development for many years. because iran has been a major client of north korea weapons. >> cnn reached out to iranian officials about that. they didn't respond. the white house maintains north korea acted alone. >> we've got no indication north korea was acting in con juchx with another country. >> north korea denies hacking sony but if pong pang pulled this off without any outside help it would be the greatest success for their shadowy hacking group called bureau 1231. >> frankly, north korea probably doesn't need the help. they've been investing in herr