A historian who has spent years looking into the unsolved lynching of two black couples in rural Georgia more than 70 years ago hopes some answers may finally be within his grasp.

A federal appeals court on Monday upheld a lower court ruling to unseal the transcripts of the grand jury proceedings that followed a monthslong investigation into the killings.

Roger and Dorothy Malcom and George and Mae Murray Dorsey were riding in a car that was stopped by a white mob at Moore's Ford Bridge, overlooking the Apalachee River, in July 1946. They were pulled from the car and shot multiple times along the banks of the river.

Amid a national outcry over the slayings, President Harry Truman sent the FBI to rural Walton County, just over 50 miles (80 kilometers) east of Atlanta. Agents investigated for months and identified dozens of possible suspects, but a grand jury convened in December 1946 failed to indict anyone.

Anthony Pitch, who wrote a 2016 book on the lynching — "The Last Lynching: How a Gruesome Mass Murder Rocked a Small Georgia Town" — has sought access to the grand jury proceedings, hoping they may shed some light on what happened.