The scientists said they were confident up to an 83 per cent level that Arafat was poisoned with polonium. The Swiss scientists, along with French and Russian teams, obtained the samples last November after Arafat's body was exhumed from a mausoleum in Ramallah in the occupied West Bank.
They found "unnaturally high levels" of polonium in Arafat's ribs and pelvis, and in soil stained with his decaying organs, Al Jazeera reported quoting the findings of the University Centre of Legal Medicine in Lausanne.
A 108-page report by the Centre, obtained by the channel, said the findings "moderately supports" polonium as the cause of Arafat's death.
Dave Barclay, a renowned British forensic scientist and retired detective, said with these results he was wholly convinced that Arafat was murdered.
"Yasser Arafat died of polonium poisoning," he said. "We found the smoking gun that caused his death. What we don't know is who's holding the gun at the time."
Barclay said the level of polonium in Arafat's rib was "about 900 milibecquerels", which is "either 18 or 36 times the average, depending on the literature".
Suha Arafat, the leader's widow, received a copy of the report in Paris on Tuesday. "When they came with the results, I'm mourning Yasser again. It's like you just told me he died," she said.
The Swiss report only examined the question of what killed Arafat. It did not address or point towards who killed him or how, Al Jazeera reported.
By October of 2004, Arafat had been holed up for more than two years in his Ramallah presidential compound, which Israeli troops had surrounded. He was elderly and frail but his medical reports show he "was in good overall health and did not have any particular risk factors", the Swiss report said.
On the evening of October 12, Arafat suddenly fell ill after eating a meal. Based on his symptoms -- nausea, vomiting and abdominal pain -- his physician initially diagnosed flu.
But his health swiftly deteriorated and doctors could not pinpoint the source of his sickness.
On October 29, Arafat was taken to Jordan. From there a French government plane carried him to Paris for emergency treatment at a military hospital.
French doctors were unable to halt his decline and he soon lapsed into a coma. On November 11, Arafat died at the age of 75. The French doctors did not conduct an autopsy, announce the cause of death or release his medical records, which heightened speculation about the cause of his sudden demise.
Image: Reuters