Swiss experts have been invited to the West Bank to test Yasser Arafat's remains for possible poisoning, the chief investigator looking into the 2004 death of the Palestinian leader said Wednesday.

The announcement followed weeks of zigzagging on the autopsy issue by officials in the Palestinian Authority, the self-rule government that Arafat established. Their conflicting positions and hesitation triggered speculation they were trying to quietly kill the investigation.

Last month, Switzerland's Institute of Radiation Physics said it had detected elevated levels of radioactive polonium-210 on stains on Arafat's clothing, reviving longstanding rumors in the Arab world that the Palestinian leader was poisoned.

However, the lab said the findings were inconclusive and that only exhuming Arafat's remains could bring possible clarity. Lab officials also said polonium decays quickly and that an autopsy would need to be done within a few months at most. They also said they needed a formal invitation to proceed with testing.

The Arab satellite TV station Al-Jazeera first published the findings of the Swiss lab. The station approached the lab on behalf of Arafat's widow, Suha, who had demanded that her husband's remains be examined and provided the lab with his clothing.

Arafat died in a French military hospital on Nov. 11, 2004, a month after falling ill at his headquarters in the West Bank city of Ramallah, where he spent the last three years of his life under Israeli siege.

French doctors have said he died of a massive stroke and suffered from a blood condition known as disseminated intravascular coagulation. The records were inconclusive about what brought about the condition, which has numerous possible causes.

The Palestinians, who from the start claimed Arafat was killed, launched an investigation that went nowhere and was dormant for years until last month's developments.

Tawfik Tirawi, the chief Palestinian official investigating Arafat's death said the Palestinians asked the Swiss lab for help. The lab confirmed that.

"We are currently studying how to adequately respond to this demand," Darcy Christen, a spokesman for the Swiss institute, said Wednesday. "Meanwhile, our main concern is to guarantee the independence, the credibility and the transparency of any possible involvement on our side," she said.

Several senior Palestinian officials, including Arafat nephew Nasser al-Kidwa, have claimed Arafat was poisoned by Israel, without presenting evidence. Israel has vehemently denied any involvement.

Palestinian officials have said they want an international probe that has the authority to summon Israeli officials. The Palestinian Authority also asked the Arab League to help pursue an international investigation. The League has said it would seek a U.N. investigation and would decide on the details in September.