Threatening emails have been sent to Sony Pictures employees and their families after a massive breach of Sony's computer network, the FBI confirmed late Friday.

While the FBI confirmed it is investigating threatening emails sent to Sony Pictures employees, it declined to elaborate. "We're not confirming the details of the threat," the FBI said in a statement.

The emailed threats say in part: "Many things beyond imagination will happen at many places of the world... Please sign your name to object the false of the company at the email address below if you don't want to suffer damage. If you don't, not only you but your family will be in danger." The text of the email was first reported by Variety.

Sony declined to comment on the emails.

On November 24, a hacking group calling itself the Guardians of Peace claimed to have obtained Sony Pictures' internal data, including its "secrets," and said it would release the data to the public if its demands were not met, according to reports. It is unclear what the hacker group was demanding.

Circumstantial evidence and speculation suggested the hackers were working on behalf of North Korea, which has denounced Sony's upcoming film "The Interview," starring Seth Rogen and James Franco as TV journalists who become embroiled in a plot to assassinate North Korean leader Kim Jong-Un. In June, North Korea's Ministry of Foreign Affairs called the movie "terrorism" and described film-makers as "gangster-like scoundrels." A spokesman for the foreign ministry said the country would retaliate if the film -- due for release next month -- is shown.

As of Friday, hackers have released around 40 gigabytes of a cache of internal Sony files and films they claim totals at least 100 terabytes -- approximately 10 times the amount of information stored in the Library of Congress. The information included passwords, employee Social Security numbers, and contracts with celebrities and distributors.

"I saw that my social security number," was in the stolen documents, said a former Sony Pictures employee who asked not to be named. "It's really bad. My friend there says it's as bad as you hear, multiplied by five."

Update, December 8 at 10:45 a.m. PT: Clarifies the amount of data the hackers have released.