Transcript for Driver in 'Monstrous' Truck Attack Was Unknown to Security Officials
Chaos screams of panic and people fleeing for their lives. Celebration for Bastille day ending in horror. Blood and bodies are where the truck turning into a lethal weapon. Deliberately crashing through groups of people after a fireworks display. This giant mine. He was just tape you know being left crimes and within split seconds. Of hearing the gunshots and I started writing ending quietly seemed to let them compete today asked. Killing dozens including children among the victims American tourists from Texas a family member tweeting the terrible news. Driver plowing through crowds for 08. Stopping only when shot by police. In the track itself we found one automatic pistol and you met my second automatic fake pistol two nationally Kofi replica. Assault rifles one grenade but balked advocate on public but they move often that we are currently investigating. Investigators believe the attacker is a 31 year old man from Tunisia leading news and with a criminal record. France's president Francois along says it is an act of terror that. Today this was a direct attack against France. And that is why this individual committed this act and the hunt is now on or any accomplices. French authorities say security cameras in the city are helping create a timeline of the assault. And hundreds of cameras capture the attacker getting into the track and later entering the promise not. Jenna freckles and ABC news London.
This transcript has been automatically generated and may not be 100% accurate.