The French hostage Philippe Verdon, who was found dead in Mali this month, was shot in the head, according to autopsy results announced on Thursday.
The geologist was taken hostage in November 2011 along with his compatriot Serge Lazarevic. Al-Qaida's North African arm, AQIM, said in March that it had beheaded Verdon in response to France's military intervention in Mali.
“After repatriating his corpse to France, the autopsy carried out on July 17 was followed up today up with an anthropological examination which is still ongoing, but already it allows us to establish that Philippe Verdon was assassinated with a bullet to his head,” the Paris prosecutor said in a statement.
A preliminary investigation into the murder was open, he said.
France sent some 4,500 troops to Mali, its former colony, in January to halt an offensive by al-Qaida-linked Islamists, ending their 10-month control of the north of the country.
Al-Qaida in the Islamic Maghreb (AQIM) said at the end of June that eight other foreign hostages it was holding, including five French nationals, were alive.
Paris knows of nine French hostages being held overseas, including seven in the African Sahel region, which includes Mali, and two in Syria.