An unknown number of elderly men are reportedly being investigated by the FBI for lynching four black victims almost seven decades ago.

Second World War veteran George W. Dorsey, his wife, Mae Murray, and Roger Malcom with his wife, Dorothy, were attacked in July 1946 on their way home by a gang of white men, believed to be Ku Klux Klan members, the Associated Press reported.

The two African-American couples were then tied to a tree and fatally shot by rifles, shotguns and pistols around 60 times near the Moore's Ford Bridge in Georgia, leaving their bodies slumped in the dirt, according to investigators.

But it was seven-month pregnant Dorothy's murder that was particularly gruesome: her unborn baby was cut out with a knife.

Although President Harry Truman dispatched the FBI to Monroe, a town about 45 miles east of Atlanta, nobody was ready to provide any details about the incident.  Several suspects were named in the FBI's 1946 investigation, but partly due to a lack of witnesses, none were ever charged. 

The two couples were known to have been employed as sharecroppers by a white farmer. However both black men had been garnering some attention months before they got brutally murdered.

While George had allegedly been secretly dating a white woman, a taboo in the segregated South, Roger had stabbed a white farmer during a knife fight 11 days earlier.

Now, 70 years later, the Equal Justice Initiative has produced names of potential suspects and campaigners that might have been involved in the decades-old crime.

An 86-year-old man in Monroe, Ga., has been questioned over his involvement in the lynchings but said he had nothing to do with the brutal killings, according to The Guardian.

"The blacks are blaming people that didn't even know what happened back then," Charlie Peppers said, denying claims of ever being a member of the Ku Klux Klan. 

Meanwhile, Daily Mail Online was awaiting on a comment from the Atlanta field office of the FBI on Monday.