A top aide says Palestinian President Mahmoud Abbas has given his permission to exhume the remains of his predecessor, Yasser Arafat.
The decision came following an Al Jazeera report that he may have died of poisoning after a Swiss institute found elevated traces of a radioactive agent reportedly on Arafat's belongings.
The institute said it needs to test Arafat's remains for conclusive findings, and Abbas has said he is willing to allow an autopsy in principle.
Abbas aide Saeb Erekat said Monday that Abbas has now given final approval, and is inviting the Swiss experts to test the remains. Erekat says "we are on the way to an autopsy''.
Earlier on Monday, Arafat's nephew said he does not believe further testing is needed. It was not clear whether the nephew would block an autopsy.
A nine-month investigation by Al Jazeera found that Arafat's final belongings - his clothes, his toothbrush, even his iconic kaffiyeh - contained elevated levels of polonium, a rare, highly radioactive element.
Scientists at the Institut de Radiophysique in Lausanne, Switzerland, who studied Arafat's personal items, said that his bones could offer more conclusive evidence that he was poisoned.
"There are no political or religious reasons that prevent researching this issue," Abu Rudeinah said, "Including the exhumation of Arafat's body by a reliable and trustworthy medical and scientific authority."
Erekat, the chief Palestinian negotiator, also called for an international committee to study Arafat's death, similar to the one investigating the death of Hariri in 2005.
"[It] is a must," Erekat told Al Jazeera. "And we will do it first through the United Nations Security Council. We hope everyone will co-operate with us, because we seek the truth and nothing but the truth."
Hamas spokesperson Fawzi Barhoum said an investigation into Arafat's death is "a national and Arab duty".
"The Hamas movement was the first to stress the need for a serious investigation into the killing of the martyr, Yasser Arafat, especially if this is an assassination and not a natural death," he said.
"It must combine all the efforts of Palestinians and Arabs to discover what happened, how Yasser Arafat was assassinated and who stands behind this crime."
Speaking to Al Jazeera on Wednesday, Suha Arafat, wife of the late Palestinian leader, said the exhumation should take place as soon as possible.
The institute studied Arafat’s personal effects, which his widow provided to Al Jazeera, the first time they had been examined by a laboratory. The items were variously stained with Arafat's blood, sweat, saliva and urine; doctors used those biological samples to look for heavy metals and other poisons.
"I can confirm to you that we measured an unexplained, elevated amount of unsupported polonium-210 in the belongings of Mr Arafat that contained stains of biological fluids," said Dr Francois Bochud, the director of the institute.
It is a highly radioactive element used, among other things, to power spacecraft. Marie Curie discovered it in 1898, and her daughter Irene was among the first people it killed, dying of leukaemia several years after an accidental polonium exposure in her laboratory.
At least two people connected with Israel’s nuclear programme also reportedly died after exposure to the element, according to the limited literature on the subject.
But polonium’s most famous victim was Alexander Litvinenko, the Russian spy-turned-dissident who died in London in 2006 after a lingering illness. A British inquiry found that he was poisoned with polonium slipped into his tea at a sushi restaurant.
There is little scientific consensus about the symptoms of polonium poisoning, mostly because there are so few recorded cases. Litvinenko suffered severe diarrhoea, weight loss, and vomiting, all of which were symptoms Arafat exhibited in the days and weeks after he initially fell ill.
Animal studies have found similar symptoms, which lingered for weeks - depending on the dosage - until the subject died. "The primary radiation target… is the gastrointestinal tract," said an American study conducted in 1991, "activating the 'vomiting centre' in the brain-stem".
Scientists in Lausanne found elevated levels of the element on Arafat’s belongings. In some cases, they were ten times higher than those on control subjects, random samples which were tested for comparison.
The lab’s results were reported in millibecquerels (mBq), a scientific unit used to measure radioactivity.
Polonium is present in the atmosphere, but the natural levels that accumulate on surfaces barely register, and the element disappears quickly. Polonium-210, the isotope found on Arafat's belongings, has a half-life of 138 days, meaning that half of the substance decays roughly every four-and-a-half months.
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“Even in case of a poisoning similar to the Litvinenko case, only traces of the order of a few [millibecquerels] were expected to be found in [the] year 2012,” the institute noted in its report to Al Jazeera.
But Arafat’s personal effects, particularly those with bodily fluids on them, registered much higher levels of the element. His toothbrushes had polonium levels of 54mBq; the urine stain on his underwear, 180mBq. (Another man’s pair of underwear, used as a control, measured just 6.7mBq.)
Further tests, conducted over a three-month period from March until June, concluded that most of that polonium - between 60 and 80 per cent, depending on the sample - was "unsupported", meaning that it did not come from natural sources.
"We got into this very, very painful conclusion, but at least this removes this great burden on me," Suha Arafat said. "At least I’ve done something to explain to the Palestinian people, to the Arab and Muslim generation all over the world, that it was not a natural death, it was a crime."
A conclusive finding that Arafat was poisoned with polonium would not, of course, explain who killed him. It is a difficult element to produce, since it requires a nuclear reactor. But the signature of the polonium in Arafat’s bones could provide some insight about its origin.