"As a result of our investigation, and in close collaboration with other US government departments and agencies, the FBI now has enough information to conclude that the North Korean government is responsible for these actions," the FBI said in a statement.
The investigation's findings follow a string of cyberattacks that Sony Pictures Entertainment experienced. The entertainment company was forced to cancel the movie theater premiere of a comedy about the Central Intelligence Agency (CIA) plotting with journalists to kill North Korea's leader Kim Jong Un after hackers, known as "Guardians of Peace", threatened to the company, its employees and theaters that they would distribute the film.
According to the FBI, North Korea's cyberattack on Sony reaffirmed that "cyber threats pose one of the gravest national security dangers to the United States," and that the "destructive nature" of this particular attack set it apart from any other the agency had investigated.
Following the investigation into the Sony cyberattack, the FBI said that it would continue to work with its federal and private sector partners help any other US company that falls victim to "a destructive cyber-attack or breach of confidential business information."
Hackers also leaked information on Sony's top executives and employees' credit card numbers, salary figures, personal passwords, and leaked footage of the films that have not yet been released in theaters.