Reuters reports: Russia said on Thursday former Palestinian leader Yasser Arafat died of natural causes, not radiation poisoning, but a Palestinian official called the finding “politicized” and said an investigation would continue.

Samples were taken from Arafat’s body last year by Swiss, French and Russian forensics experts after an al Jazeera documentary said his clothes showed high amounts of deadly polonium 210.

The Swiss said last month their tests were consistent with polonium poisoning but not absolute proof of the cause of death. The Russian finding was in line with that of French scientists who said earlier this month that Arafat had not been killed with polonium.

“Yasser Arafat died not from the effects of radiation but of natural causes,” Vladimir Uiba, head of Russia’s state forensics body, the Federal Medico-Biological Agency, was quoted as saying by the Interfax news agency.