By Jerry Mitchell, The (Jackson, Miss.) Clarion-Ledger

JACKSON, Miss. — The long, slow march of prosecuting unpunished killings from the civil rights era continues Tuesday when James Seale goes on trial.

The 71-year-old former crop-duster faces federal kidnapping and conspiracy charges in connection with the abduction and slayings of Henry Dee and Charles Moore, two African-American teenagers, in May 1964.

Dee and Moore, both 19 years old, were abducted, beaten, tied up, weighted down and tossed into the Mississippi River, where they drowned, according to a copy of the FBI case file that has been made public. If convicted, Seale could be sentenced to life in prison.

Seale's trial marks the sixth civil rights-era case that has been prosecuted in Mississippi since 1990, when a grand jury here indicted Byron De La Beckwith for the 1963 assassination of Medgar Evers, the field secretary for the Mississippi NAACP.

A cascade of prosecutions followed the Beckwith conviction. The tally so far: Authorities in seven states have re-examined 29 killings from the civil rights era and made 29 arrests, leading to 22 convictions.

The most recent came in 2005, when Edgar Ray Killen was sentenced to 60 years in prison for orchestrating the 1964 killings of civil rights workers James Chaney, Andrew Goodman and Michael Schwerner. The killings were depicted in the 1988 film Mississippi Burning.

Although the passage of time makes these cases tougher to prosecute, the push to pursue them is gathering momentum.

MORE: Photo of murder victim surfaces 43 years later

On May 9, an Alabama grand jury indicted former state trooper James Bonard Fowler on a charge of murder in the shooting death of Jimmie Lee Jackson in 1965.

"Prosecutors across the country are starting to look at these cases, realizing there needs to be closure," said District Attorney Michael Jackson of Marion, Ala., who is prosecuting Fowler.

The FBI case file lays out the following description of how Dee and Moore died:

On May 2, 1964, Dee and Moore were hitchhiking from Meadville when Ku Klux Klansmen coaxed them into their vehicle. Deep in the woods, the Klansmen repeatedly beat the teens, believing they knew something about gun running in Franklin County. Finally, one of the pair claimed the guns were being hidden in a church, hoping to stop the violence. That didn't work.

The Klansmen loaded Dee and Moore into their vehicle and hauled them across the Mississippi River. There, the Klansmen tied them up and weighted them down with a Jeep motor block before dumping them into the river 2 miles south of King, La.

On July 12, 1964, a fisherman discovered Moore's body. Dee's body was found the following day.

Four months later, Mississippi state police and FBI agents arrested Seale and Charles Edwards on murder charges. At the time, an FBI agent confronted Seale and told him they knew he and others took Dee and Moore "to some remote place and beat them to death," the case file says.

"You then transported and disposed of their bodies by dropping them in the Mississippi River," the case file says Seale was told by an FBI agent. "You didn't even give them a decent burial. We know you did it. You know you did. The Lord above knows you did it."

"Yes," Seale is quoted in the case file as replying, "but I'm not going to admit it. You are going to have to prove it." Former FBI agent Edward Putz, who testified about the exchange during a recent hearing, identified the agent quoted in the case file as Leonard Wolf.

When state police and FBI agents arrested Edwards, he admitted his involvement in the beatings but said Dee and Moore were still alive when he left, according to the case file. Despite that admission, authorities dropped the charges several months later, and the slayings of Dee and Moore was not officially pursued until the case was reopened in 2000.

Asked at the time during an interview for a story in The (Jackson, Miss.) Clarion-Ledger if he had anything to do with the crime, Seale replied, "I ain't in jail, am I?"

Seale, who has been held in the Madison County jail since Jan. 24, now faces trial in U.S. District Court. Moore's brother, Thomas, convinced U.S. Attorney Dunn Lampton of Jackson in 2005 to pursue the case.

Edwards, now 72, was granted immunity for his grand jury testimony, according to a grand jury document made public by the defense. He is on the list of prosecution witnesses.

Seale's attorneys, assistant federal public defender Kathy Nester and George Lucas, senior litigator for the public defender's office, are not commenting on the case.