The ACLU on Monday filed an appeal brief demanding that the Central Intelligence Agency (CIA) hand over data on its secretive global drone program, including the identities of people killed by airstrikes carried out by the U.S. military in Yemen, Somalia, and Afghanistan.

No information on the program, including its legal justification, has been officially disclosed to the public.

The Intercept last week published The Drone Papers, a months-long investigation into the program that used a cache of intelligence documents leaked by an anonymous whistleblower to reveal the operation's internal structure and the chain of command underlying the military's aerial assassinations. In the aftermath of the report, the ACLU and several other human rights and civil liberties organizations demanded immediate accountability for the officials involved.

With Monday's appeal brief, the ACLU is breathing new life into a Freedom of Information Act (FOIA) lawsuit filed in January 2010 to force the CIA to give up the data.

The information "is crucial to the public’s ability to understand government policy and hold policymakers accountable for their decisions," the brief states. The FOIA was put into law to "guarantee the public access to the kind of information the CIA is now withholding."

In addition to the CIA's program, the ACLU is also seeking information on a similar operation being conducted by the U.S. Department of Defense. Together, the two programs are estimated to have killed thousands of civilians in Pakistan, Yemen, Somalia, and Afghanistan, according to independent calculations by journalists, analysts, and other sources on the ground in those countries.

The case has been slow to move through federal courts. A 2013 decision by a three-judge panel in Washington, D.C. rejected the CIA's argument that disclosing data on its drone program would jeopardize national security—but in June of this year, Judge Rosemary Collyer with the D.C. district court ruled (pdf) in favor of the agency, allowing it to keep the information secret.

But Collyer got it wrong, says ACLU deputy legal director Jameel Jaffer. He writes in an op-ed published Tuesday:

According to credible, independent studies, the strikes have killed more than three thousand people, including hundreds of civilians. Although many Americans have raised questions about the effectiveness, morality, and lawfulness of the government’s drone campaign, the government has exercised tight control over the information available to the public.

The ACLU filed a FOIA request in the case "to compel the release of information that is crucial to the public’s ability to understand government policy and hold policymakers accountable for their decisions," Jaffer wrote.