Palestinian Authority President Mahmoud Abbas confirmed Sunday that Russian experts will join a team of Swiss and French investigators in exhuming the remains of Palestinian leader Yasser Arafat.

Abbas said he hoped that Russian involvement would help “new facts… arise or be known about the causes of death.”

Arafat’s death in a French hospital in November 2004 has remained a mystery for many. While the immediate cause was a stroke, the underlying source of an illness he suffered in his final weeks has never been clear. That led to conspiracy theories that he had cancer, AIDS or was poisoned.

The new probes come after a Swiss lab discovered traces of a deadly radioactive isotope on clothes said to be Arafat’s, sparking new accusations he was poisoned.

Though Arafat’s widow, Suha Arafat, has signed off on exhuming the late leader’s body, his relatives have come out against his remains being removed from their Ramallah tomb.

Arafat’s sister, Khadija, called on the Palestinian Authority on Sunday to investigate her brother’s cause of death without digging up the grave. Nasser al-Kidwa, a member of the Fatah leadership and Arafat’s nephew, agreed that there is no need for an exhumation because, he asserted, everyone knows Israel is behind the death.

According to the Palestinian Authority, Arafat’s exhumation is set to take place on November 26.