The Obama administration must acknowledge the existence of an independent investigation into former White House senior economics adviser Austan Goolsbee’s alleged unauthorized access to the Koch brother’s tax returns, a court ruled Tuesday.

A federal judge ruled the Treasury Inspector General for Tax Administration (TIGTA) must disclose to watchdog group Cause of Action whether records of an investigation exist.

Cause of Action filed a Freedom of Information Act (FOIA) lawsuit after TIGTA refused to confirm or deny the existence of the investigation in what is commonly known as a "Glomar response."

"The court has ruled that the federal government cannot hide behind confidentiality laws to prevent Americans from knowing if our President has gained unauthorized access to their tax information," Cause of Action executive director Dan Epstein said in a statement Tuesday. "This is a decisive win for all Americans and for government transparency and accountability."

Former White House Council of Economic Advisers chairman Austan Goolsbee sparked a mini-scandal in 2010 when he told reporters during a background press briefing that Koch Industries—the company of libertarian philanthropists Charles and David Koch—paid no income taxes.

Conservative lawmakers and activists said Goolsbee’s statements not only unfairly singled out the president’s political opponents but also used confidential IRS documents to do so.

TIGTA announced in response to a letter from six Republican senators that it was launching an investigation into Goolsbee’s comments and whether he violated the law. However, the report was never released to the senators or the public.

TIGTA refused to confirm or deny the existence of the investigation in response to several FOIA requests from the Washington Free Beacon, Koch Industries, and Cause of Action. The agency general cited a statute forbidding the unauthorized release of any citizen’s tax returns.

However, the court ruled Tuesday that the statute did not bar the agency from confirming the existence of an investigation, and that the agency had waived its right to apply other exemptions by previously acknowledging the report.

"The fact that TIGTA has publicly announced that it has investigated unlawful disclosures of, or access to, that body of information protected by statute as ‘return information’ strongly suggests that the fact of an investigation is not, itself, ‘return information,’" the court wrote.

The court cited an Aug. 10, 2011 email obtained by The Washington Examiner from Treasury Special Agent Daniel K. Carney, in which Carney wrote, "The final report relative to the investigation of Austan Goolsbee’s press conference remark is completed, has gone through all the approval processes."

The White House has consistently denied that it illicitly reviewed Koch Industries’ tax documents. However, it has offered shifting explanations for where Goolsbee got the information he disclosed in the briefing.

An administration official told Politico that the White House got the information from testimony before the President’s Economic Recovery Advisory Board (PERAB) and from Koch’s own website.

When then-White House press secretary Robert Gibbs was asked to name the sources, he did not offer a specific answer. "I don’t know the answer off the top of my head on that," Gibbs said. "Again, I can see if there’s better information on that."

The White House later said Goolsbee was just repeating something he recalled reading.