My grandfather, prosecuting attorney in a small Mississippi hill town for more than 40 years, believed that a nation’s concept of justice to the individual is at the heart of its civilisation. A county prosecutor who opposed the death penalty and a member of the Mississippi legislature who doubted the Resurrection, he fought all his life against a judicial system with the capacity to be vindictive, unjust, pitiless or vengeful. Over the years this man, who wore seersucker suits from April until October, has grown in my memory to be morally as tall as Atticus in To Kill a Mockingird.

Watching the prosecuting attorney in the Michael Jackson trial made me think about my grandfather. Maybe it is grafting hopeful thinking onto sepia memory but I reckon Papa would never have allowed that case to go to court. I wonder what he would have made of another trial, less than 40 miles from his legal patch. The first I heard about it was Friday evening in the kitchen, listening to PM on Radio 4 as I trimmed my last asparagus of the season. It was the final news slot and I lifted my head when I heard the words ‘Mississippi’ and ’41 years later, a murder trial’, the names ‘Chaney, Schwerner and Goodman’. In the coolness of an English summer evening I sat down and wept.

The tragic journey of the three young civil rights workers-two white northerners, one local black-into the heart of Klan country on Sunday, June 21, 1964, to investigate the burning of the black Mount Zion Methodist Church, is now a part of American history. The details are familiar from the film Mississippi Burning: how they were arrested at 3pm by a deputy sheriff on the outskirts of Philadelphia, Mississippi, kept in jail until 10.30 that night, released and stopped again 10 miles outside of town; the gangland-style killing by Klansmen; their burial in a dam under construction in a remote area of the county. By the time the FBI found their bodies-44 days later-my own family had watched a cross burn in our front yard, lived under a siege of bomb threats. The crime? To try and penetrate the frozen world of fear and violence.

What Mississippi Burning failed to show was that no one was ever tried for the murders. In 1967 the federal government returned 19 indictments for conspiracy to violate the civil rights of the three dead men. Witnesses said that Klan leader Edgar Ray Killen wasn’t present at the killings, but Preacher Killen was the mastermind who summoned the Klansmen and chose the killing and burial sites. Eleven members of the jury wanted to convict him but one held out-a woman who could ‘never convict a preacher’.

This trial will be one of the last of the South’s ‘atonement trials’, with a new generation of jurors and prosecutors snatching the old dragons from their air-conditioned pick-ups and putting them where they belong. In 1994 Byron de la Beckwith was convicted of the 1963 murder of civil rights activist Medgar Evers. Three years ago, Bobby Frank Cherry was convicted of the 1963 bombing of a Birmingham church that killed four black girls.

Folks will always say that 40 years has passed, let old men die in their own beds, but I inherited prosecutor’s genes. I believe that murder is murder, justice is justice. It’s never too late to work to restore faith and trust. As the abolitionist Theodore Parker put it: ‘The arc of the moral universe is long, but it bends towards justice.’

This article first appeared in Country Life magazine on June 23, 2005.