A Swiss laboratory said on Wednesday it will help investigate the 2004 death of former Palestinian Authority Chairman Yasser Arafat only if it receives guarantees its findings will not be used for political purposes.

A committee looking into the Arafat’s death has asked the Swiss Radiophysics Institute, which found traces of polonium on Arafat’s clothing provided by his widow for a recent Al Jazeera television documentary, to examine his remains.

“We have been invited by the Palestinian National Authority and we are currently studying the most appropriate way of responding to this request,” Darcy Christen, spokesman for the institute, told Reuters.

“Meanwhile, our main concern is to guarantee the independence, the credibility and the transparency of any involvement that we may have,” he added.

Arafat’s widow, Suha, called for an autopsy of her husband’s body after the Swiss lab found the traces of polonium on his belongings.

Medical files released for the first time last month portray Arafat as a robust 75-year-old whose sudden health crisis, a month before his 2004 death, was initially blamed on viral gastroenteritis.

An Israeli specialist, Dr. Joseph Zimmerman, who reviewed the medical file, said Arafat’s early symptoms were not consistent with viral gastroenteritis, but also said poisoning seemed unlikely, even by a radioactive agent such as polonium-210.

Zimmerman pointed out that Arafat’s platelet counts dropped suddenly and stayed low and that he eventually exhibited signs of liver dysfunction.

“This is not typical of poisoning,” he said, adding that a bacterial infection could have caused these symptoms.

Tawfiq Tirawi, head of the committee looking into the death, told reporters on Wednesday the Swiss institute was seeking assurances before sending experts to Ramallah, but did not disclose the nature of those guarantees.

“The content of our correspondence pertained to the necessity of their arrival and our welcoming of their presence in Palestine as quickly as possible, but they have some legal issues and legal procedures,” Tirawi said, according to Reuters.

“We’ve asked for (the Swiss team’s) arrival at full speed…the leadership has resolved to grant them any investigations they might request,” he added.

Amir Rappaport of the Israel Defense website recently published an account of Arafat’s final days as told by Israeli officials. The account said that Israel allowed Arafat to be released from his Ramallah compound and be flown to France, where he received treatment for complications of leukemia.

While Arafat’s condition began to improve under French care, Israeli sources reported that French doctors then tried a dramatic procedure – a total blood transfusion, in which all of Arafat’s blood was replaced with donor blood. Arafat went into a coma during the procedure and never woke up. He died on November 2011, 2004, and was buried in Ramallah.