one internet blog says "the interview" has been shared illegally about 750,000 times. the fbi is not commenting on report that is north korea probably was not behind the hack on sony pictures. here is cnns brian todd with that part of the story. >> reporter: the forensic trail of the sony hack is mysterious, difficult to follow and now is sparking increasing doubt over the fbis belief that hackers working for north korea is responsible. >> it's clear to us based on forensic and other evidence we have collected that unequivocally they are not responsible for orchestrating or initiating the attack on sony. >> reporter: his cyber security firm did an investigation on the hack. norse and cloudflare said the malware used is similar to