The explosion injured seven people after the vehicle – filled with fuel canisters and firework mortars – exploded. Officials said all injuries were minor.
Authorities said they were yet to determine any motive.
“I’m comfortable calling it a suicide with a bombing that occurred immediately after,” Las Vegas Sheriff Kevin McMahill said during a Thursday afternoon press conference.
Livelsberger rented the Cybertruck on 28 December in Denver, Colorado. He has decades of experience with the US military, having served in the Army and National Guard.
He entered the active duty Army in December 2012, serving as a special operations soldier.
The US Army said he was on approved leave at the time of his death.
Livelsberger’s father spoke to the BBC’s news partner CBS and said his son was currently serving in Germany and on leave to visit Colorado and see his wife and eight-month-old daughter.
Livelsberger’s father said he last spoke to his son at Christmas and that everything seemed normal.