U.S. closer to formally blaming North Korea for Sony hack

Sony cancels release of " The Interview" 01:36

Sony Pictures Entertainment pulled the plug on "The Interview", bowing to threats of potential violence at movie theaters.

Sony hack again reveals corporate vulnerabili... 02:54

In a statement, Sony said: "We have decided not to move forward with the planned December 25 theatrical release." The studio said it made that decision with "paramount interest in the safety of employees and theater-goers.

"The Interview" features reporters on a mission to kill the leader of North Korea. An online threat Tuesday warned moviegoers to stay away, saying: "The world will be full of fear. Remember the 11th of September."

The warning seemed to come from hackers calling themselves "Guardians of Peace". That's the same group behind a wide ranging cyber-attack on Sony.

Law enforcement sources say investigators believe that the Guardians are state-sponsored hackers inside North Korea. Sources tell CBS News that the US government has determined the North Korean government is behind the hack. But, the U.S. government has not yet publicly named a suspect. And the regime of Kim Jong Un has denied any involvement in the cyber-attack.

The assault on Sony is one of the most destructive and disruptive cyber-attacks to hit any U.S. company. Sony has already lost millions of dollars, and maybe more in prestige, to hackers who have stolen films and destroyed critical computer records.