The driver of a lorry used to attack Bastille Day celebrations in Nice is believed to have been a 30-year-old French-Tunisian criminal well known to the police for armed attacks.
"He was known to the police for violence, and using weapons, but had no direct links with terrorism," said an investigating source. "His identity car was found in the lorry. He had French and Tunisian nationality."
He is believed to have been a resident of Nice.
A search of his vehicle uncovered a pistol, a larger gun, and a number of fake weapons and grenades.
He boarded the truck "in the hills of Nice" before driving down to the promenade, according to CCTV footage, regional president Christian Estrosi said on Friday.
So far there have been no claims of responsibility for the attack, which is being considered an act of terrorism.
There have also been no claims of accomplices, but Mr Estrosi said the investigation should focus on finding anyone the man worked with.
"Attacks aren't prepared alone. Attacks are prepared with accomplices," Mr Estrosi said. "There is a chain of complicity. I expect it to be unveiled, discovered and kept up to date."