"First time in Vegas, and then, like, the whole thing, what you know from movies only -- I was shocked," said Christine Gerstenberger, who was visiting from Germany.
Thursday's incident started about 4:20 a.m. with a dispute in the valet lot of the Aria hotel, about a block away, Gillespie said. Investigators haven't confirmed the cause of the altercation, but he said it spilled onto the street.
The Maserati's passenger and other witnesses are helping detectives piece together what happened, he said. The "top priority" for police is to find those who were inside the Range Rover, which sped away from the intersection.
John Lamb, who was inside Caesars Palace, told CNN affiliate KLAS that he heard the commotion and saw the taxi on fire from a window.
"There was a loud bang, and I heard two other booms. I looked out my window at Caesars Palace ... and could see the fireball," he told KLAS.