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When Raphael Kogun's uncle fell ill two years ago, his brothers knew exactly what to do. They called in a witchdoctor to find out who was responsible for their relative becoming "bagarup" - pidgin for sick, from the English "buggered up".
The finger of blame was pointed at a middle-aged couple from Kogun's village in the highlands of Papua New Guinea, who were accused of being possessed by evil spirits and placing a curse on the man.
"We ran after them and we chopped their heads off with an axe and a bush knife," said Kogun, a 27-year-old farmer from Goroka, in Eastern Highlands province.
"I felt sorry for them but they were witches, they deserved to die. If they were still alive they could hurt people with their magic."
Two of his brothers were arrested under the Act of Sorcery incorporated into PNG's criminal code, but the case collapsed because witnesses were too terrified to testify.
Once hailed as an untouched Shangri-la, the mist-shrouded highlands of Papua New Guinea are undergoing a dramatic resurgence in sorcery and witchcraft.
Age-old beliefs in black magic and evil curses are back with a vengeance in jungle-clad mountain valleys which were unknown to the outside world until the 1930s.
The revival is being fuelled by a spiralling Aids crisis and the collapse of health services, sapping villagers' faith in Western medicine.
Barely educated villagers living in remote mountain valleys are blaming the increasing number of Aids deaths not on promiscuity or a lack of condom use but on malign spirits.
Alleged witches - mostly women, but some men and even children - have been subjected to horrific torture before being hanged or thrown off cliffs.
The number of witch killings has been estimated at 200 a year in the neighbouring province of Simbu alone, although definitive figures are impossible to come by.
A report by Amnesty International in September found there was a "conspiracy of silence" surrounding the murders.
"The police do little to penetrate this silence. Very few sorcery-related deaths are investigated and the perpetrators are rarely brought to justice," the report concluded.
Belief in magic is ubiquitous throughout Papua New Guinea, where more than 850 languages are spoken by 5.5 million people.
In the highlands they are known as "sangumas" and can assume the form not only of humans, but animals such as dogs, pigs, rats and snakes.
When Papua and New Guinea were separate Australian colonies, colonial patrol officers known as "kiaps" and their native auxiliaries suppressed sorcery killings.
But since independence in 1975, the old ways have gradually undergone a gruesome renaissance along the spine of saw-toothed peaks which divides PNG in two.
A surge in the illegal growing of marijuana in the emerald green valleys has contributed to black magic paranoia, experts say.
The recent acquisition of automatic weapons, replacing traditional bows and arrows, has also emboldened the groups of young men, who typically carry out the torture.
"We're seeing a big rise in witchcraft cases. We hear of a killing almost every week," said Hermann Spingler, a German Lutheran pastor who heads the Melanesian Institute, a cultural study centre in Goroka.
"If someone in Papua New Guinea dies prematurely, people ask not what caused the death, but who. They take the law into their own hands and torture people to make them 'confess'. They drag women on ropes behind vehicles, burn them with hot wire, chop off hands, fingers. People have been buried alive."
As in medieval Europe, accused sorcerers face a ghastly Catch-22 predicament. "If you don't confess, you die. If you do they'll kill you," said Spingler.
He expects more witch murders as PNG's Aids crisis worsens. The country has the highest rate of Aids in the Pacific region, and the Government estimates that around 2 per cent of the population is HIV-positive.
That is almost certainly an underestimate. "The problem is far worse than the official statistics show. In some antenatal clinics 30 per cent of women are [HIV] positive," said Claire Campbell, an Australian Aids campaigner working for the World Health Organisation.
The fear is that promiscuity, prostitution, sexual violence and a tradition of men having several wives could drive the country into an Aids epidemic, with half a million infected with the disease by 2025.
The problem is exacerbated by the backwardness of the remote highlands, which were only penetrated by Australian gold prospectors in 1930.
The Australian colonial government had assumed the highlands were too wild and rugged to be inhabited. Instead the prospectors stumbled on a thriving culture of more than a million people, a "land that time forgot" which had never been encountered before.
More than 75 years on, most villages are still miles from the nearest road, their inhabitants living on a traditional diet of sweet potato, pigs and the game they can hunt in the forest.
Schools and aid posts established by the Australian colonial authorities have been abandoned, their funding siphoned off by corrupt politicians.
More than 30 years after independence, there is still no road linking the capital, Port Moresby, with any major town. To travel north from the south coast one must catch a plane - or, if you are a local, use the vast network of paths which wind their way through the jungle.
"It's only 75 years since the first white man walked over the hills," said Mal Smith-Kela, PNG's only white provincial governor.
Born in Essex, England, he emigrated to Australia as a 10-year-old, flew helicopters with the Australian Army in the Vietnam War and became a successful businessman in PNG.
"I've flown into villages where they tried to work out what sex the helicopter was by looking at the exhaust pipes. People are reverting to what they know best."
Last month, police in Goroka uncovered the grisly killings of four women accused of using sorcery to cause a fatal road crash. After being tortured with hot metal rods and made to confess, they were murdered and buried upright in a pit.
A banana tree was planted on top and it took police months to learn of the murders, which are believed to have taken place in October.
"The villagers believe they have to kill the 'witches', otherwise the whole clan is at risk from black magic," said Jack Urame, 38, a member of the Dom tribe who has researched sorcery killings for the Melanesian Institute.
Witchcraft killings, once confined to the highland provinces, are now occurring in coastal areas as mountain people migrate to towns like Lae and Port Moresby in search of jobs.
"Children are now witnessing these things - the belief in sorcery and witchcraft is being passed on to the next generation," Urame said.
