In a video posted on social media, the assistant director of the FBI’s cyber division, Brett Leatherman, vowed yesterday to hunt down the members of a cybercriminal group going by the name of ShinyHunters, the same group that last week claimed to steal reams of sensitive data from the FBI itself.

“You know how to find us, and we know how to find you,” Leatherman said in the video, encouraging the prolific group of loosely connected data extortionists to come forward and share information or face the consequences. “I suggest you reach out first while the choice is still yours.”

The FBI says it is “aggressively” investigating the breach and how hackers got ahold of sensitive FBI employment information, including whether the hackers got into third party software or the FBI’s own internal systems. In a statement emailed to NPR, a FBI spokesperson said the bureau is working “around the clock to investigate the cyber incident involving FBIJobs.gov and is in regular communication with anyone who may be impacted.”

It’s still unclear how much information was stolen, though media organizations and threat intelligence researchers have already verified the authenticity of some of the stolen materials. Meanwhile, a defacement message was posted on the FBI’s jobs website late last week where ShinyHunters took credit for the attack, and the site was temporarily taken down.

Current and former FBI employees familiar with the matter, who spoke to NPR on condition of anonymity because they feared reprisal for speaking about an ongoing investigation, said many employees first found out about the breach from media reports. They suggested there could be as many as several terabytes of text files in the data tranche, including FBI job applications, details on promotions, information on sensitive job postings, family details, medical data, and more. Those same employees, particularly those who have retired, say there’s growing frustration with FBI leadership including FBI Director Kash Patel about the lack of communication about the breach, exactly who is impacted, and how the FBI plans to protect its current and former employees. Some retired employees who worked undercover might need protection services like relocation assistance or even name changes if their data is exposed publicly.