United States federal agents have joined an investigation of an attack on computers belonging to Sony Pictures Entertainment. The Federal Bureau of Investigation says the cyber-attack on the film producer took place last month.
Later this month, Sony Pictures plans to release a comedy film called The Interview. It tells about an imaginary plot against North Korean leader Kim Jong Un. Since the attack, many people are wondering if North Korea was responsible for hacking into the computers.
North Korean officials have denounced the movie and promised to "mercilessly destroy" anyone connected to it. The film stars actors Seth Rogen and James Franco. The U.S. Central Intelligence Agency asks for their help in a plot against the life of North Korean leader Kim Jong Un.
The Interview is set for release in theatres on December 25. The movie will be shown in more than 60 countries, including the United States. North Korea has sent protests to President Barack Obama and the United Nations. And it has called the distribution of the film, "undisguised sponsoring of terrorism."
Frank Cilluffo leads the Homeland Security Policy Institute at the George Washington University in Washington, D.C. He says that there is good reason to believe that North Korea was responsible for the cyber-attack.
"They certainly have both the motive and the capability. They made their intentions loud and clear when the Foreign Ministry threatened that they will mercilessly destroy anyone who dares to hurt the supreme leader. And they also have the capabilities, since they have been investing very heavily in asymmetric means of warfare and technologies, generally, and computer network attack and cyber capabilities, specifically."
Mr. Cilluffo adds that North Korea is investing more money in building up its cyber-attack capabilities than any other country. He suspects the cyber-attacks will likely increase. But he says there is currently no proof that North Korea is to blame for the attack on Sony's computer networks.
"What we lack at this stage is foolproof attribution. In other words, we don't have a smoking keyboard that they in fact were behind it, or whether or not proxies or those sympathetic to North Korea's causes were behind it, or if someone else altogether is behind it."
This week, North Korea firmly denied reports that it was to blame for the cyber-attack. A North Korean diplomat in New York told VOA his country has nothing to do with the attack. "My country publicly declared that it would follow international norms banning hacking and piracy," he added.
The hacking caused suspension of Sony Pictures's e-mail systems. Employees were completely unable to use email and other networking systems. Sony has since re-established some of the affected systems. Internet security experts were brought in to repair the damage.
After the attack, unreleased copies of five movies were posted on the Internet without the film studio's approval. Reportedly, hackers also stole personal medical and payment information of thousands of Sony Pictures employees.
I'm Jonathan Evans.