Businessman Herve Cornara was brutally murdered by an alleged ISIL supporter. (Supplied)  A man who beheaded his boss in France has denied any religious motivation, investigative sources say, muddying efforts to pin down the reasons for an attack which bore the hallmarks of a jihadist act.  Yassin Salhi, 35, on Sunday confessed to decapitating his employer and pinning his severed head to the fence of a gas factory in eastern France in a macabre display that included two Islamic flags.  However according to a source close to the investigation, Salhi, who was known to security services for radicalisation, "denies any religious motivation to his act".  "He hasn't explained" why he attached the head to the fence, or shouted out "Allahu Akbar"(God is greatest) as firefighters overpowered him as he attempted to open bottles of acetone in a warehouse at the factory, said the source on condition of anonymity.  Salhi drove his delivery van into the Air Products warehouse on Friday, causing an explosion and alerting firefighters who made the grisly discovery of the decapitated corpse of 54-year-old Herve Cornara.  Investigative sources say a fellow employee had reported a quarrel between Salhi and Cornara two days before the murder, after the employee dropped a crate containing expensive goods.  While the attacker apparently denies any Islamist motivation, police discovered he had sent a gruesome selfie with the severed head to a number in Canada believed to belong to a French jihadist thought to be in Syria.  The jihadist, named Yunes-Sebastien, belonged to the same radical movement from the eastern Franche-Comte region as Salhi, said sources close to the case.  French Interior Minister Bernard Cazeneuve said Salhi had been on a national security watchlist from 2006 to 2008 and later raised red flags for his links to radical movements between 2001 and 2014.  Police took Salhi, dressed in a hospital gown and wearing a bulletproof vest, with his head covered by a white cloth, to his apartment on Sunday in an effort to find his passport and verify this information, to no avail, investigative sources said.  Hundreds of French citizens have left for Iraq or Syria to wage jihad and Prime Minister Manuel Valls said Sunday that 1,800 people in France were "linked" in some way to the Islamist cause.  Salhi, a married father-of-three, has been in police custody for some 72 hours, and can be held for 96 hours without charge.  The gruesome beheading shocked France which has been on high alert since 17 people were killed in three days of Islamist attacks in January, beginning with a shootout at the satirical magazine Charlie Hebdo.  Do you have any news photos or videos?
Yassin Salhi has confessed to beheading his boss at a French gas factory as it emerged he sent a gruesome "selfie" of his deed to Syria.