Court ruling throws into doubt FBI's hunt for elderly racist killers

An elderly white member of the Ku Klux Klan who was responsible for one of the most brutal killings of the civil rights period when he tied engine blocks to the feet of two black teenagers and threw them alive into the Mississippi river has had his conviction overturned by a US appeals court.

The decision to throw out the three life sentences imposed last year on James Ford Seale, aged 72, throws into doubt attempts by the FBI to bring to justice the perpetrators of scores of lynchings and murders that swept the South of the US during the 1950s and 60s.

Three judges sitting on the fifth US circuit court of appeals ruled that the case against Seale, was went to trial last May, 43 years after the original murders, had fallen outside its sell-by date.

The ruling conceded that the statute of limitations that imposes a time limit on legal action "in some cases deprives society of its ability to prosecute criminal offences" but argued "that is the price we pay for repose".

The murders of Charles Moore and Henry Dee, both aged 19, were among the most notorious acts of white southern supremacists who sought to silence opposition to segregation through violence and intimidation.

The year of the slayings, 1964, was known as Freedom Summer in the South because of efforts by civil rights campaigners to overcome barriers to black people registering to vote.

On May 2 1964 Seale and other members of the Mississippi branch of the White Knights of the KKK kidnapped the teenagers, who they suspected of being involved in civil rights activity, as they were hitchhiking to a party.

The men were tied to a tree and beaten 30 or 40 times with a stick, before being thrown into the river with a Jeep engine block tied to their legs.

An FBI informant inside the Klan alleged that Seale told him later that he decided to throw them alive into the water as to shoot them first would have splattered blood over the boat.

The victims' partially decomposed bodies were found months later only as a result of an on-going search into a separate slaying in which three civil rights activists were killed in events captured in the film Mississippi Burning.

Seale was arrested in 1964 but no action was taken against him - according to federal prosecutors because the local police were in cahoots with the KKK.

For many years he was presumed dead, but he was tracked down by Thomas Moore, brother of one of the dead teenagers, together with a Canadian documentary crew and the case was reopened.

Seale was rearrested in January 2007.

Seale's conviction came largely on the testimony of another Klan member Charles Edwards who was controversially granted immunity from prosecution in return for appearing in the witness stand.

Moore told the Mississippi paper the Clarion Ledger that he was surprised by the acquittal of his brother's murderer. "It's a shock, but there's nothing I can do. The truth was told, and the law is the law."

The civil rights division of the federal justice department in Washington is now reviewing the appeal court ruling with an eye to its implications not only in this case but in up to 100 other unsolved murders from the civil rights period that are being looked at again by the FBI.

A special unit of the bureau was set up last year to pursue the most promising cases in the hope of bringing closure to some of them before the individuals involved become too infirm to prosecute or died.

Seale, who pleaded not guilty at his trial, has been held at a federal prison in Terre Haute, Indiana, where he has been receiving medical treatment for cancer and other conditions. It is possible that he will remain in jail pending a further appeal against his release by theprosecutors.

Contacted by the Clarion Ledger, his wife Jenny said: "Oh man, yes, he's coming home. I've prayed and I've prayed. Now you can get the man who's really guilty."

She did not specify which guilty party she had in mind.

· The following correction was printed in the Guardian's Corrections and clarifications column, Saturday September 13 2008. In the report above we said that, according to federal prosecutors, no action was taken at the time because local police were in cohorts with the KKK. We meant cahoots. This has been changed.