Sony Pictures canceled its planned release of “The Interview” after hackers threatened violence against theaters that played the film, as U.S. officials concluded that North Korea was behind the broad cyberattack on the company.

Officials are still gathering evidence and are trying to build a clearer picture of who directed the hacking and how, according to people familiar with the investigation, but the focus on North Korea elevates the issue from a question of corporate security to national security.

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