Elton Thompson was out drinking when he was bludgeoned to death by a miner called Frank. He was 14. Arturo Balcazar was a shopkeeper. He was gunned down on a riverboat as his wife looked on. Alan Welch was 54. He was clubbed to death with tree trunks and branches after being accused of theft.

Three men, three murders but apparently one common cause: the global economic crisis that has sent gold prices through the roof and aggravated an already cut-throat scramble for gold in the South American Amazon.

Across the Amazon all-time record gold prices, which are the result of investors seeking a safe haven from the US and European economic slump, are reportedly adding fuel to a chaotic jungle gold rush. This has brought violence, disease and conflict to the mineral-rich rainforests of Brazil, Guyana, Peru, Bolivia, Colombia and Venezuela.

"There is a direct correlation between the price of gold and what we have to deal with these days," David Ramnarine, a Guyanan police commander, told the Demerara Waves news website after a string of gold-related killings in his country, including those of Thompson, Balcazar and Welch.

Guyana's top police official, Henry Greene, also linked the ballooning price of gold to an upsurge in killings and lynchings in remote mining camps where prostitution, gun-slinging and drug abuse is also rife. "It is all related and has a lot to do with the price. A lot more people than normal are going to the interior as there is a lot of money in gold right now," he told the Caribbean Life website.

A front-page story in Guyana's Kaieteur News last month warned of chaos in the country's "deadly gold bush" – the same region where British explorer Walter Raleigh unsuccessfully sought a mythical city of gold in the late 16th century.

"A toxic mix of gold, greed and alcohol has resulted in a spate of brutal murders in the interior," the newspaper reported, cataloguing killings involving miners, jewellers and shopkeepers working at the gold mines.

Over the border in the Brazilian Amazon, indigenous communities are also increasingly alarmed at the presence of wildcat miners on their lands.

Nearly two decades after 2,000 Yanomami Indians lost their lives during the last big gold rush, indigenous leaders in Brazil's Roraima state fear history may be repeating itself.

More and more impoverished miners are pouring on to their lands in search of gold, leaving a trail of environmental and human destruction.

"I'm worried – my people are suffering," said Dário Vitório Kopenawa Yanomami, health co-ordinator for the tribe's Hutukara association, who believes there could now be as many as 2,000 illegal miners operating inside the Yanomami reserve.

"The miners are hiring planes to come into the reserve. Their entry is constant," he said. "It is dangerous to go where they are. They are all armed.

"If we go near them they will kill us. We are getting information that the invaders are getting close to our lands. The Yanomami are asking for support," he added.

In an interview last month, Dario's father, Davi Kopenawa Yanomami, the Yanomami's best-known leader, warned: "Every day an average of six unauthorised flights take off for the Yanomami reserve. Shops are selling lots of equipment for mining. Illegal runways have been reopened."

At 2,000, the number of illegal miners currently operating in the reserve would still be a fraction of the estimated 40,000 that brought death and destruction during the 1980s and 1990s.

But activists fear the price of gold, which has been as much as 40% higher than last year, is luring more adventurers, who are reactivating illegal airstrips on Yanomami land in order to ferry miners in and out of the region's goldmines.

Last month the Folha da Boa Vista newspaper, from Roraima's state capital, reported that on "Gold Street", a dusty city centre mining hub where much of the illegal gold is sold, prices have risen from 48 Brazilian reais (£16.80) a gram two years ago to as much as 96 reais now.

"The high price of gold is increasing the thirst for mineral reserves in our indigenous territories," said Janete Capiberibe, an Amazon MP who is petitioning police and indigenous officials in Brasilia on the Yanomami's behalf. She hopes to set up a public hearing to discuss the impact of the gold rush on them and other Amazon tribes.

Capiberibe warned that as well as violence and illness, contact between indigenous people and miners could lead to "alcoholism and prostitution – a change in behaviour that profoundly damages the indigenous culture".

In neighbouring countries the effects of the surge in gold prices are also being felt. Colombia's president Juan Manuel Santos has claimed that members of leftist guerrilla group Farc are turning their attentions to gold mining, as a result of a government offensive against its cocaine production operations. The rising price of gold means mining has become a lucrative and alternative source of revenue for the group.

Meanwhile, a recent study by academics from Duke University in North Carolina found that between 2003 and 2009 mining-related deforestation rose six-fold in Peru's Madre de Dios region. This area is home to perhaps the biggest single gold rush in South America.

The study, which linked the growing destruction to rising gold prices, said native forests and wetlands were being transformed into a "vast wasteland of ponds".

In mid-August, the price of gold approached a record high of $1,830 an ounce, amid speculation that it could reach $2,000 by the end of the year.

In Guyana the killing went on. Daniel Higgins, 48, and his 22-year-old son were reportedly shot and hacked to death before being buried in a mining pit by an excavator.

Their murders were recorded in the latest gory dispatch from the Kaieteur News: "The motive seems to be greed," the story suggested. "The high price of gold has made tempers short."

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