A federal appeals court has ruled that grand jury evidence long sought by civil rights activists and historians in a 1946 mass lynching case in rural Georgia must remain sealed.

Despite the historical significance of the case, the U.S. Court of Appeals for the 11th Circuit in Atlanta ruled Friday that federal judges do not have the authority to unseal federal grand jury records, except for a limited set of circumstances governing grand jury rules of secrecy.

The 8-to-4 decision reversed a lower court’s ruling in 2017 that the evidence should be unsealed. That ruling, which had been viewed as a breakthrough in the unsolved murders of two black couples in 1946 by a mob of white men in Walton County, Ga., was also affirmed in 2019 by a three-judge panel made up of members of the circuit court, which heard the case after the Justice Department appealed the lower court’s decision. Last June, the full court voted to rehear the case, which led to Friday’s ruling.

The victims in the lynchings, Roger and Dorothy Malcom and George and Mae Murray Dorsey, were dragged from their car at gunpoint on July 25, 1946, tied up and shot about 60 times at close range in the attack, which was widely considered to be one of the last mass lynchings in American history. It came to be known as the Moore’s Ford lynchings.