A man suspected of beheading a businessman at a French gas factory in June has been found dead in his prison cell.
Deputy prosecutor Jean-Michel Bourles in Evry, a Paris suburb, said Yassin Salhi had committed suicide in Fleury-Merogis prison.
The former delivery driver faced preliminary murder and terrorism charges and was suspected of ties to Islamic State extremists.
The attack in France's south-east put the country back on high alert after January's deadly extremist attacks.
French prosecutors said Salhi lured his boss into a van, knocked him unconscious and beheaded him. Salhi allegedly carried a long-bladed knife, a gun and two brand-new flags emblazoned with the Muslim declaration of faith.