Authorities and celebrities were grappling with how to respond to a website that posted what appears to be private financial information about top government officials and stars such as Jay-Z and Mel Gibson.
The justice department said on Monday the FBI was investigating how the Social Security number, address and a credit report of FBI director Robert Mueller ended up on the site.
The site also posted the same information about Los Angeles police chief Charlie Beck, and the department said it was investigating the matter.
In addition to Jay-Z and Gibson, other targeted stars included Beyonce, Ashton Kutcher, Kim Kardashian and Paris Hilton. Info posted about vice-president Joe Biden and former secretary of state Hillary Clinton did not include credit reports but included addresses and other sensitive information.
Social Security Numbers posted on Gibson, Jay-Z and others matched records in public databases.