A federal appeals court panel in Washington, D.C., seemed skeptical of arguments by the government on Monday that the FBI has fully complied with an open records request about its practice of impersonating journalists in criminal investigations.

The Associated Press and Reporters Committee for Freedom of the Press argue in a lawsuit filed in 2015 that in searching for records responsive to their Freedom of Information Act (FOIA) request, the FBI ignored certain locations where the records could have been found.

In oral arguments Monday, Judges Brett Kavanaugh, David Tatel and Laurence Silberman of the U.S. Court of Appeals for the D.C. Circuit repeatedly pressed Justice Department lawyer Joseph Busa about why the FBI did not explain in greater detail how it conducted the searches.

Tatel said that D.C. Circuit case law shows that merely “passing along” a FOIA request to different components of the agency isn’t enough to satisfy the FBI’s burden under the law. The agency should, Tatel said, describe how a search was done.

Busa argued that in those cases, the requests were for specific records related to a certain case or had some other identifier. In this case, he said, the request was for “all records” pertaining to the FBI’s practice, which he described as “nebulous.” But the judges were not satisfied.

“Why wouldn’t you describe exactly how they did it?” Silberman asked Busa, referring to the FBI’s responses about how it conducted the search.

The Associated Press and Reporters Committee asked the FBI for three categories of documents: those pertaining to a 2007 investigation in which the FBI was known to have impersonated an AP reporter, any records about agents impersonating news media since then, and any internal guidelines and other documents about the policy generally.

The FBI did not provide any documents until the groups sued in 2015. The groups also claimed the FBI grouped parts of the FOIA request together illogically, searching for some records in some systems while looking for different types of records in others.

The groups appealed to the D.C. Circuit this year after U.S. District Judge Richard Leon dismissed their lawsuit in February. Leon ruled that the FBI had conducted an adequate search, concluding the agency did not have to search every records system available.

Leon ruled the FBI only needed to search record systems that likely held the responsive records, which he believed they had done in good faith.

Monday, all three judges on the panel asked Busa about a declaration from the section chief of the FBI’s Record/Information Dissemination Section, David Hardy, which explained that that different FBI offices were contacted and told to search for records in response to the requests. Busa said that because many individual employees were asked to form their own searches on their files and emails, any declaration explaining the search would be too long.

Silberman also said he was puzzled about why the FBI director’s office wasn’t searched, noting that as an official at the Justice Department in the 1970s, Silberman found the files of former FBI Director J. Edgar Hoover hiding in plain site in the director’s office. Busa said the policy and training documents sought would not necessarily be in records in the director’s office.

The judges also asked Reporters Committee lawyer Katie Townsend, who argued for the plaintiffs, which locations she thought should have been searched that were not. She listed the Inspector General’s Office, which released a report on the FBI’s practice of impersonating reporters in 2016, any offices that dealt with congressional inquiries about the issue, as well as other FBI field offices.

The FBI’s practice of impersonating reporters came to light in 2014, when a different FOIA request revealed that in a 2007 investigation, an FBI agent impersonated an AP reporter to install malware on a juvenile suspect’s computer. The juvenile was suspected of making bomb threats at Timberline High School near Seattle.

The revelation about the FBI’s practice caused an uproar in the media, prompting then-FBI Director Jim Comey to write a letter to the editor in The New York Times defending the practice.