REUTERS/Eric Gaillard
Although the man who has not yet been named was shot dead by French police, his identity papers were found in the truck.
According to French newspaper Nice Matin, the name of the attacker is Mohamed Lahouaiej Bouhlel, a father-of-three. This has not been confirmed by authorities.
The attacker shot at the crowd from the truck before accelerating and smashing into them, killing at least 84 people and injuring hundreds more.
The newspaper reported that many people close to him were currently being questioned by police.
Police have confirmed that the driver was born in 1985 and of Tunisian origin.
The attacker lived in Nice and was already known to police for minor criminal offences but was not under surveillance of French authorities and was not listed as a person that could pose a threat to the country.
His home was searched by police on Friday morning. On top of the caliber 7.65 pistol he used to shoot at police and the crowd, the refrigerated truck he drove into the crowd was also filled with explosives. He had rented the truck two days before the attack according to French newspaper Le Figaro.
No group has yet claimed responsibility for the attack.