The FBI is investigating ShinyHunters’ claim that it stole personal data belonging to thousands of current and former employees, applicants and agents through a suspected vulnerability in the FBIJobs.gov website. The group says it disrupted the site to pressure the FBI to amend a May advisory about its activities, rather than to demand money, but the alleged breach could expose staff to retaliation if sensitive information is leaked.

ShinyHunters claims to have taken two to three terabytes of data, including names, addresses, phone numbers, spouses’ names and some medical and professional information. The FBI has not confirmed that the breach occurred and says it is still determining whether the entry point was its own systems or a third-party provider; the site remained inaccessible while officials warned personnel to protect themselves. The group has not said what it will do if its one-week deadline is missed, although experts believe it could publish the data online.