(JTA) — Yasser Arafat was not poisoned, according to a French-administered test of the late Palestinian leader’s remains, casting doubt on a Swiss report.

The results of the report by French experts found high levels of polonium in Arafat’s body, Reuters reported, but attributed them to radon gas in his tomb. The Swiss report had suggested that the high levels of polonium came as a result of poisoning.

Arafat died in 2004 after weeks of illness, with a stroke as the official cause of death. In the past year, however, investigations into a possible poisoning have intensified.

Arafat’s widow, Suha, claims that her husband was murdered and trusts the Swiss test regardless of the French test’s results. Some Palestinians have long claimed that Israel murdered Arafat, a claim Israel denies categorically.

In addition, Palestinian Authority investigator Tawfiq Tirawi, tasked with identifying the perpetrators of Arafat’s murder, said he was close to naming suspects. Tirawi has been searching for perpetrators for more than a decade.