The federal agency’s surveillance of staffers feared to be leaking confidential information about medical devices was wider than previously thought.

The US Food and Drug Administration conducted thorough surveillance on its own scientists in an effort to stop leaks of sensitive information pertaining to approved medical devices that the staffers feared were capable of damaging public health. While the FDA was previously known to capture screenshots of emails sent by its staff, newly public documents show that the probe was much wider, with more than 80,000 pages of information collected from the computers of scientists working within the agency. The documents also listed names—including 21 FDA staff members, members of Congress, journalists, and external researchers—of people the FDA claimed were colluding to spread negative information about the agency.

The dispute between the FDA and its own scientists started in 2008 when members of a review committee complained to members of Congress that the agency approved some cancer screening devices against the advice of the committee, which had warned that the machines might dose patients with dangerous levels of radiation. The move spurred the agency into spying on the staffers’ communications pertaining to the device issues.

Then, in mid-2010, the FDA’s internal investigation grew to include monitoring communications between the disgruntled staffers and others outside the agency. Last September, some of the targeted FDA employees filed a lawsuit against the agency for snooping on their private communications, but the scope of the surveillance was only revealed recently when, seemingly by mistake, the public website of a private document-handling contractor that works for the FDA posted the captured documents, which the New York Times reviewed thoroughly.

Some of the legislators named in the FDA’s probe have harsh words for the agency’s actions. Emails from a former staff member of Senator Charles Grassley (R-IA) showed up in the documents collected by the FDA. “The FDA is discouraging whistleblowers,” Grassley told the New York Times. Officials at the agency, he added, “have absolutely no business reading the private e-mails of their employees. They think they can be the Gestapo and do anything they want.”

The FDA acknowledges that it conducted the surveillance, but officials there maintain that they did not seek to quell communication between agency employees and outside interests, but rather to monitor whether sensitive information was being improperly shared. The lawyer for the FDA staffers who are suing the agency told the New York Times that he’ll be seeking an injunction in federal court this month to stop any ongoing surveillance on employees still at the agency.