Swiss scientists have found evidence suggesting Yasser Arafat may have been poisoned, TV station Al-Jazeera has reported, prompting new allegations by his widow that the Palestinian leader was the victim of a "shocking" crime.
Palestinian officials have long accused Israel of poisoning Arafat, a claim Israel has denied. Arafat died under mysterious circumstances at a French military hospital in 2004, a month after falling ill at his Israeli-besieged West Bank compound.
The findings appear to be the most significant so far in an investigation into Arafat's death initiated by his widow, Suha, and the satellite TV station Al-Jazeera.
Last year, Switzerland's Institute of Radiation Physics discovered traces of polonium-210, a deadly radioactive isotope, on some of Arafat's belongings.
Soil and bone samples were subsequently taken from Arafat's grave in the West Bank.
On Wednesday, the station published the Swiss team's 108-page report on the soil and bone samples. The results "moderately support the proposition that the death was the consequence of poisoning with polonium-210," the report said.
Repeated attempts to reach the main author, Patrice Mangin, or the Lausanne-based institute's spokesman, Darcy Christen, were unsuccessful Wednesday night.
Suha Arafat told Al-Jazeera she was shocked and saddened by the findings.
"It's a shocking, shocking crime to get rid of a great leader," she said, without casting specific blame. In his final days, Arafat "was so ill, losing everything, his immunity," she said. "He was shrinking day by day."
Arafat's widow demanded that a Palestinian committee that has been investigating her husband's death now try to find "the real person who did it".
The committee also received a copy of the report, but declined comment.
The head of the committee, Tawfik Tirawi, said details would be presented at a news conference in two days, and that the Palestinian Authority would announce what it plans to do next.
Raanan Gissin, a former Israeli government spokesman, reiterated Wednesday that Israel had no role in Arafat's death.
"It was a government decision not to touch Arafat at all," he said, adding that "if anyone poisoned him, it could have been someone from his close circle."
Arafat died Nov. 11, 2004, a month after falling violently ill at his Ramallah compound. French doctors said he died of a massive stroke and had suffered from a blood condition known as disseminated intravascular coagulation, or DIC. But the records were inconclusive about what led to the DIC, which has numerous possible causes, including infections and liver disease.
Polonium is a rare and highly lethal substance. The element can be a byproduct of the chemical processing of uranium, but usually is made artificially in a nuclear reactor or a particle accelerator.
Less than 1 gram (0.035 ounces) of the silver powder is enough to kill. Polonium's most famous victim was KGB agent-turned-Kremlin critic Alexander Litvinenko, who died in London in 2006 after the substance was slipped into his tea.
The examination of the Arafat's remains found "unexpectedly high levels" of polonium-210, the Swiss team wrote.
Derek Hill, a professor in radiological science at University College London who was not involved in the investigation, said the levels of polonium-210 cited in the report seem "way above normal".
"I would say it's clearly not overwhelming proof, and there is a risk of contamination (of the samples), but it is a pretty strong signal," he said. "It seems likely what they're doing is putting a very cautious interpretation of strong data."
He said polonium is "kind of a perfect poison" because it is so hard to detect unless experts look for it using specialised equipment generally found only in government laboratories.