The suspected extremist who decapitated his boss before ramming a vehicle into a chemical plant near Lyon has admitted killing his manager beforehand, a source close to the investigation said on Sunday.

The suspected extremist who decapitated his boss before ramming a vehicle into a chemical plant near Lyon has admitted killing his manager beforehand, a source close to the investigation said on Sunday.

Yassin Salhi, a 35-year-old French lorry driver, told detectives he had killed Hervé Cornara in a parking area before arriving at the plant in Saint-Quentin-Fallavier, 18 miles (30km) south of Lyon, where he attempted to cause an explosion on Friday.

Salhi was transferred to Paris for further questioning on Sunday afternoon. Several French media reported that during questioning he had been “confused” as to the motives behind the attack, citing personal problems linked to family issues and his job.

The TV news channel iTele said Salhi had told police he had wanted to kill himself and stage a media coup by dressing it up as a terrorist act. The news channel said Salhi had told police he had acted alone, according to the Guardian.

Meanwhile, Reuters news agency reported that the Frensh police has linked the suspect to a militant now in Syria.

It said that examination of one of Salhi's mobile phones revealed that he had taken a picture of himself with the severed head before his arrest and sent the image to a Canadian phone number. Canadian authorities said on Sunday they were assisting the investigation.

The phone number belongs to a French national, known by his first name Sebastien-Younes, who has been in Syria since last year, the same source said, confirming media reports. His last known location was the Islamic State stronghold of Raqqa.

According to other French media reports, Salhi told police he had argued with Cornara and with his own wife before the killing. One of their work colleagues, quoted on the website of the television station i-Tele, also said the two men had clashed days earlier after Salhi dropped a pallet of fragile equipment.

The suspect, whose wife and sister were released on Sunday after two days of questioning, is said by French security services to have associated with hardline extremists over more than a decade, and had previously been flagged by them as a potential risk.