A LYNCH mob stopped a car carrying two black couples and their white employer on July 25th 1946. One of the black men, Roger Malcolm, had just been given bail after stabbing a white farmer. The mob tied up all four African-Americans and shot them 60 times. Their white boss, who was not harmed, said he could not identify any of the perpetrators.

The lynching that took place near Moore’s Ford Bridge in Walton County, Georgia, is still unsolved. A marker was erected 2.4 miles west of the spot in 1999. But few other such signs exist at similar sites in the South.

Between 1877 and 1950 almost 4,000 black southerners were lynched, according to a new report by the Equal Justice Initiative (EJI), a human-rights group. That is 700 more than previously reported. During the days of Jim Crow, a black man could be murdered for speaking “disrespectfully” or for knocking on the door of a white woman’s house. In 1904 a crowd in Mississippi sipped lemonade and nibbled devilled eggs as they watched a black couple being mutilated and burned. “Our willingness to romanticise this period necessitates that we deal too with the racial terrorism and violence at this time,” says Bryan Stevenson of the EJI.

Georgia saw more such murders (586) than any other state, followed by Mississippi. Tyrone Brooks, a member of Georgia’s House of Representatives, has spent years researching the lynching at Moore’s Ford Bridge with the Southern Christian Leadership Conference (SCLC), after past investigations went nowhere—despite the greater willingness of locals to share information about the murders in recent years. He has also organised annual re-enactments since 2005, and believes white anger over blacks trying to vote partly motivated the killings. On February 13th he sent a letter to Charles Grassley, chairman of the Senate Judiciary Committee, asking for an investigation and hearings into what happened. “We have no faith in law enforcement agencies any more, as they’ve already had since 1946 to look into this case,” says Mr Brooks.

His campaign is unlikely to get far. A letter last year to the Judiciary Committee’s chairman at the time, Patrick Leahy, went unanswered. And it does not help that Mr Brooks faces trial in April for allegedly misappropriating money from two charities—charges which he denies, and which his lawyer puts down to sloppy book-keeping rather than fraud.

After 69 years the murderers of Moore’s Ford Bridge are either dead or very old. The odds of any of them being put on trial are remote. But even if justice cannot be done, other forms of commemoration are valuable, argues Stan Deaton of the Georgia Historical Society. Signs at lynching sites might mark “literally and figuratively how far society has come”, he says. However, many small towns are reluctant to erect them, for fear they might “pick off the scab” from old wounds, he says.

Newnan, a pretty town with three markers commemorating Confederate history, is one of them. It has turned down requests for a sign to remember Sam Hose, a black man who was castrated and burned alive there after being accused of rape and murder in 1899. The town refused in part because no descendants of Hose lived there, and because no one wanted to upset the family who allegedly suffered at his hands, says Winston Skinner, a local journalist. “But avoiding the truth does not permit the kind of reconciliation the South needs,” says Mr Stevenson. And Mr Deaton agrees: “History is not about condemning or celebrating the past, but about trying to understand the human condition.”