Tunisian-born Mohamed Lahouaiej Bouhlel, a 31-year-old delivery driver, was reported to be a French passport holder who lived in the Riviera city and was regularly in trouble with the law.
At least 10 children are among the dead following the "cowardly and barbaric" atrocity that left at least one British national among the many injured. Officials fear the death toll will rise.
As hundreds remained in hospital - including 18 fighting for their lives in intensive care - anti-terrorist judges opened an investigation into "mass murder" and investigators searched the home of the driver in the Abattoirs area of Nice.
Investigating sources said Bouhlel's last appearance in a criminal court was as recently as March, when he was found guilty of violent contact. Despite this, he had no known links with terrorism and was not under surveillance.
An investigating source said: "An operation is currently underway at the dead suspect’s home in Nice. It is being raided by officers."
Bouhel left his French identity card in the hired 19 tonne lorry used to murder dozens of people on Thursday night.
A woman living in the same shabby apartment block as Bouhel today told how he "seemed very weird". She told The Telegraph, "He lived alone. He said very little to anyone and wasn’t very polite. He wouldn’t hold the door open for you."
His truck had zigzagged through crowds massing on the Promenade des Anglais, killing anyone he could.
After being stopped by armed police, who fired bullets into the lorry’s windscreen, the so far unnamed man exchanged fire with officers using a 7.65 pistol, before being shot dead.
A search of the vehicle uncovered a pistol, a larger gun, and a number of fake weapons and grenades.
The fact that the killer was known to the authorities will be of grave concern to those trying to prevent terrorist attacks in France.
A recent Paris parliamentary investigation into last year’s attacks identified multiple failings by France’s intelligence agencies.