By Stephanie Holmes
When three hangman's nooses were suspended from a tree in a school playground in a small Louisiana town, it sparked a chain of events which has fuelled a furious debate over race, justice and symbolism in the US.
The Jena noose incident spawned a series of copycat acts
The coils of knotted rope which swung in the shade of the tree recalled the nooses used to hang black men in collective lynchings carried out by white mobs in the southern states as recently as the 1940s.
The incident in the small town of Jena, which culminated in a group of black youths being charged with attempted second-degree murder for allegedly beating a white boy, has spawned a series of copycat acts.
Nooses have been hung on doors, pinned up in workplaces and slipped into letters.
New York's government is now considering criminalising any representation of the noose as a hate crime.
Some African-American analysts argue that the recurring use of the noose as an instrument of intimidation reveals deep and unresolved racial tensions in US society.
"The noose, in the context of Louisiana, is a symbol of a technique of racial intimidation," explains Professor Anita L Allen, of the University of Pennsylvania's law school.
"Up until the 1940s, African-Americans were ritualistically hung from nooses in trees, killed and tortured - and this memory persists."
Columbia University students denounced this noose on a teacher's door
Mark Potok, director of the Southern Poverty Law Centre's Intelligence Project, which monitors hate groups operating across the US, agrees.
"The noose in US history is intimately associated with the Ku Klux Klan. It became the symbol of the worst the southern white supremacists could do," he told the BBC News website from Alabama.
At Columbia University, in New York, a black professor arrived at work earlier this month to find a noose hung from the door of her office.
Nooses have also recently been reported to have been found in a coast guard cadet's bag and outside a Manhattan post office.
Mr Potok argues that the rise in the number of incidents involving nooses echoes an increase in the number of hate groups across the US, which has grown by 40% over the past six years.
"There really has been an outbreak of incidents," he says. "They reflect a much wider white backlash. This is not a handful of Klansmen and neo-Nazis but widespread anger."
In Jena, the nooses - reportedly in the three school colours - were hung from a tree where whites used to congregate, a day after a black pupil asked the headmaster if he could sit in its shade.
Some public zones remain divided along race lines
Months later, a white teenager was violently attacked and kicked at the school, allegedly by six of his black schoolmates.
The response of the local justice department, which initially charged five of the six with attempted second degree murder and set prohibitively high bail costs for them, provoked anger.
Some of charges were subsequently downgraded.
According to Anita L Allen, although the history of lynching is widely known, it is not on the school curriculum and the "full horror and terror" of the noose's significance may remain unclear to a 16-year-old who would see it as merely an "intimidating or cheeky" act.
The underlying problem, she insists, is the fact that the use of public spaces - such as the tree for shade - continues to be defined by skin colour.
"American society is much too full of what are metaphorically 'white-only shade trees' and 'black-only shade trees'," Ms Allen says. "We are much too content to let these pockets of segregation persist."
She sees the schoolyard as the place where broader race struggles are played out and erupt into conflict.
"If you have playgrounds that are single-race or school proms - as often happens in the US south - that are for one race or the other, or students who dine separately from one another... then I think we are asking for trouble."
She points to a recent Supreme Court ruling which threw out voluntary affirmative action programmes operating in schools in Seattle and Louisville, Kentucky to encourage mixed-race schools.
"Now we are back-pedalling on that approach and the legal context for desegregation is being destroyed and the social and political will to desegregate the society is disappearing with the result that we live in this bifurcated black/white world," she says.
But Mr Potok reckons that the US needs to look beyond its borders, rather than to its backyards, for the source of race tensions.
"You can see it from the comments in reaction to this case on the internet. I would argue that racial nationalism is going up. It is a function of globalisation, of the weakening nation-state."
'Riot and mayhem'
For Mychal Massie, the head of Project 21, a group of conservative African-Americans linked to a Washington-based think-tank, the whole case has been blown out of proportion by the US media because of what he believes is an intrinsically liberal bias.
"They made it an issue of race when it should not be about race. You had seven thugs, who were black, who beat a white young man, beat him unconscious," he told the BBC News website.
"That's not race, that's riot and mayhem! They should be held accountable for their actions."
He insists the noose cases are random, isolated incidents linked up by the media, and that Jena's violent school brawl is not connected to the "teenage prank" of months earlier.
"We cannot take these incidents and say that they are indicative of a pandemic of racism that is spreading across America, it is just not the case," he said.
In Jena, the shade tree - which had itself become a symbol of conflict in its own right - has been cut down, but the issues it exposed remain deeply rooted.