The conclusion of research conducted on the remains of Palestinian leader Yasser Arafat, is displayed on a screen during a news conference at the University Hospital forensic center in Lausanne, Nov 7, 2013. [Photo/Agencies]

LAUSANNE - Swiss scientists who analyzed samples from the corpse of Yasser Arafat Thursday confirmed the abnormal presence of radioactive polonium, but poisoning remains a hypothesis, not a certainty.

At the press conference which was held Thursday afternoon and after their test report was hand over on Tuesday to representatives of the late Palestinian leader's widow Suha Arafat and the Palestinian National Authority, Patrice Mangin, director of the University Centre of Legal Medicine Lausanne-Geneva (CURML), told reporters that the investigations can not exclude that the polonium is the cause of the death of Arafat, but the results can not conclude that Arafat was poisoned.

Mangin noted that several factors such as the long delay between Arafat's death and the start of investigations made analysis difficult, having said that they had to work on samples partially destroyed.

Arafat died at a French military hospital in 2004 from an undisclosed or unknown condition. No autopsy was performed at the death of Yasser Arafat, and no clear medical information on the cause of death has been released.