The Tesla Cybertruck explosion and fire at the entrance of the Trump Hotel in Las Vegas Wednesday morning is being investigated as a possible terrorist act, according to a law enforcement official who has been briefed on the investigation.

The explosion was caused by fireworks and explosives in the bed of the rental Cybertruck, which had no faults, according to data.

Authorities say they know that a highly decorated Army soldier shot himself in the head inside a Tesla Cybertruck packed with fireworks that exploded outside Trump's Las Vegas hotel.

Matthew Livelsberger -- the driver of the Tesla Cybertruck that exploded outside the Trump International Las Vegas Hotel -- shared "grievances" in two letters.

Tricia Kean outlines what we're learning about Matthew Livelsberger from his ex-girlfriend, Alicia Arritt. Investigators say Livelsberger died by suicide in the explosion outside the Trump International Hotel last week.