Tawfik Tirawi, head of a Palestinian committee investigating the death of Palestinian leader Yasser Arafat, said Friday Israel is the "prime and only suspect." A team of Swiss researchers released a report Wednesday saying Arafat might have died from polonium poisoning. A Russian report released at the same time said it couldn't conclude that Arafat was poisoned at all, Haaretz reported. "The outcome of the comprehensive report on the levels of Polonium-210 and the development of his illness does not give sufficient evidence to support the decision that Polonium-210 caused acute radiation syndrome leading to death," said Dr. Abdullah Bashir, the chairman of the Palestinian medical committee, quoting the Russian report. Tirawi, speaking in reaction to the findings, said it's clear the former leader was deliberately poisoned while eating dinner in 2004, Britain's The Daily Telegraph reported. "The basis [of the investigation] is to find who stands behind the assassination of Yasser Arafat and who had the technical and scientific resources for that," Tirawi said during a news conference in the West Bank city of Ramallah. "We say that Israel is the prime and only suspect to be accused and we will continue to have a complete investigation of the to find out all the details and factors of the case."