A former Ku Klux Klan member has been charged with kidnapping and conspiracy in connection with the 1964 murders of two black teenagers in Mississippi.
The case was reopened after a campaign by Mr Moore's brother
James Seale, a 71-year-old former sheriff's deputy, denies the charges.
The dead men, Charles Eddie Moore and Henry Hezekiah Dee, were long thought to have been abducted by the white supremacist group while hitchhiking.
The beaten and decomposed bodies of the two 19-year-olds were found in the Mississippi River two months later.
Mr Seale, who was arrested on Wednesday, appeared in court in Jackson, Mississippi, charged with two counts of kidnapping and one count of conspiracy to commit kidnapping.
Prosecutors said that in May 1964 Mr Seale aimed a shotgun at the two black men while fellow Ku Klux Klan (KKK) members beat them with tree branches.
According to the indictment, Mr Seale and the others attached weights to the two men, took them out on the water in a boat and threw them into the river.
Mr Seale was first arrested over the killings in 1964
Their bodies were discovered two months later by the FBI during a search for three missing civil rights workers.
Mr Seale and a second man were arrested at the time. Consumed by the civil rights case, the FBI turned the case over to the local authorities, which threw out all charges.
The second suspect, church deacon Charles Marcus Edwards, 72, has not been charged.
Mr Seale has been jailed pending a bail hearing set for Monday.
If convicted, Mr Seale will face a maximum term of life imprisonment on each count of the indictment.
The case was re-opened following a campaign by the brother of one of the dead men. For years, Mr Seale's family told reporters that he had died.
In 2005, Thomas Moore alerted the authorities to the fact that Mr Seale was living a few miles from where the kidnappings took place.
Speaking after the arrest, Thomas Moore said he had cried for the first time in 50 years.
"It's not going to bring [Charles'] life back. But some way or another, I think he would be satisfied," Mr Moore said.
The FBI is currently re-opening several cases from the civil rights era before suspects die.
During the movement of the 1950s and 1960s, dozens of black people were killed by white people who wanted to retain racial segregation.
Few of the crimes were solved, partly because some of the perpetrators were protected by state and local officials.