Federal officials may not use private email accounts to get around public records laws, a federal judge ruled on Tuesday.

The U.S. Court of Appeals for the D.C. Circuit overturned a lower court decision in which judges dismissed claims from the Competitive Enterprise Institute (CEI), a conservative think tank that attempted to obtain correspondence from a top White House official through the Freedom of Information Act (FOIA).

The White House’s Office of Science and Technology Policy (OSTP) said it did not need to search for or turn over records held by the head of the OSTP on a private email account as part of the open records request.

In addition to official White House email, John Holdren, the director of the OSTP, also sent and received emails from a domain at the Woods Hole Research Center.

Throughout the case, the government argued that “[d]ocuments on a nongovernmental email server are outside the possession or control of federal agencies, and thus beyond the scope of FOIA.”

Judge David Sentelle, the chief judge of the U.S. Court of Appeals for the D.C. Circuit, disagreed with that reasoning and ordered the lower court to reconsider the case.

“If a department head can deprive the citizens of their right to know what his department is up to by the simple expedient of maintaining his departmental emails on an account in another domain, that purpose is hardly served,” Sentelle wrote.  

“It would make as much sense to say that the department head could deprive requestors of hard-copy documents by leaving them in a file at his daughter’s house and then claiming that they are under her control,” he said.

While Holdren did forward some of his work-related emails from his private email account to his government one — yielding 110 pages of responsive documents in the FOIA request — Sentelle said the agency still had to do a search to ensure no other undisclosed records remained in the account.

The case is not yet final and has been remanded for further proceedings.

CEI applauded the ruling on Tuesday.

“While today’s ruling is a major victory for government transparency, it’s stunning that it takes a court decision for federal employees to be held accountable to the law,” said Marlo Lewis, CEI senior fellow, in a statement. “The ‘most transparent administration in history’ has proven over and over that it has no intention of actually letting the American public know what it is doing. Just think, if today’s ruling had gone the other way, the implication would be that all government business could be transacted on private email and be invisible to citizens, completely gutting FOIA – absurd!"

"Director Holdren is not the first agency head to be found using private email for his government work, but as we continue our legal battle in this case, we seek for this unlawful behavior to come to an end," Lewis added.

The ruling was released the same day that FBI Director James Comey announced his department is not recommending criminal charges against Hillary Clinton over her use of a private email server while secretary of State.

Clinton, the presumptive Democratic presidential nominee, has said she deleted personal emails from her server while handing over work-related messages to the State Department, which has been releasing them in batches in response to FOIA requests and lawsuits.