PARIS • The first sign that the Nice truck attacker was planning something violent came about eight months ago, when he snapped a picture of a news story headlined: "Man deliberately rams car into cafe terrace."
Around the same time, Mohamed Lahouaiej Bouhlel showed a friend a video of a hostage being decapitated, according to Paris prosecutor Francois Molins.
"When (the witness) expressed his surprise, Mohamed Lahouaiej Bouhlel said, 'I am used to it,'" said Mr Molins on Monday.
Many people interviewed by investigators described the Tunisian father of three as "someone who did not practise the Muslim religion, ate pork, drank alcohol, took drugs and had an unbridled sexual activity".
But Mr Molins said a "clear, recent interest in the radical extremist movement" had emerged before Bouhlel rammed a 19-tonne truck into a crowd last Thursday, on Bastille Day, in the Mediterranean resort city of Nice, killing 84 people.
However, there has been no clear link established to the Islamic State in Iraq and Syria group (ISIS), which claimed the attack, saying Bouhlel was one of its "soldiers".
Analyses of his computer and cellphone uncovered images and Internet searches showing a fascination with violence and militant movements such as Al-Qaeda and ISIS.
From July 1, Bouhlel made near- daily searches for video of nasheeds - religious chants used in ISIS propaganda. He also searched for information about the terror attack on a gay nightclub in Orlando, Florida, that left 49 dead, and the Paris suburb of Magnanville, where a police couple were killed last month. Both were linked to ISIS.
He also had on his computer photos of Al-Qaeda founder Osama bin Laden and Mokhtar Belmokhtar, a former commander of Al-Qaeda's north Africa branch.
There was also a photo of the cover of satirical weekly Charlie Hebdo, where 12 people were gunned down in an attack claimed by Al-Qaeda in Yemen, in Paris in January last year.
Mr Molins said the Nice attack was "of a premeditated nature".
From July 1, Bouhlel had sought information about the Bastille Day fireworks and did searches such as "horrible fatal accident", "terrible fatal accident" and "shocking videos not for sensible viewers".
He also researched truck rental agencies and a weapon shop.