Apple is also trying to determine how photos that had been stored on its iCloud system were pulled by the hackers, according to The Associated Press.
Actress Mary Elizabeth Winstead tweeted that she had previously deleted the photos of herself that were postedSunday. "Knowing those photos were deleted long ago, I can only imagine the creepy effort that went into this," Winstead tweeted. "Feeling for everyone who got hacked."
Shortly after the photos spread online on Sunday, the leak was traced back to a user on a 4chan message board.
This isn't the first time celebrities have had their private photos posted online as the result of hacking. Previous victims include Scarlett Johansson, Mila Kunis, Vanessa Hudgens and Christina Aguilera. They were all hacked by the same man, who was sentenced to 10 years in jail.