"What happened will not be tolerated," Gillespie said, vowing that the shooters would be "found and prosecuted to the full extent of the law."
Jogger Eric Lackey was on his way back to the New York-New York hotel when he snapped a cellphone photo of the blazing scene moments after the crash. Black smoke billowed from the flaming taxi, amid popping sounds from the fire.
Lackey, of Forest Hill, Md., said a security officer in a yellow shirt performed CPR on a person on the sidewalk while police officers canvassed a small crowd of perhaps 15 onlookers gathering at the scene.
"Police were asking if anyone was still in the vehicles and if they heard gunfire," Lackey told The Associated Press. "That's when I realized it wasn't just a regular accident."
The effects of the shooting and crashes were felt hours later as the Strip remained closed, leading to snarled traffic, until it reopened late Thursday night.
The fiery rampage shocked tourists.
"We get stabbings, and gang violence," said Mark Thompson, who was visiting from Manchester, England, with his wife, "but this is like something out of a movie. Like 'Die Hard' or something."
Police said they were contacting authorities in three neighboring states about the Range Rover Sport that had a car dealer's advertisement in place of a license plate.
In Southern California, the California Highway Patrol alerted officers in at least three counties to be on the lookout for the SUV.
Witnesses also told police the SUV and Maserati had come from the nearby CityCenter area, the home of Aria, just south of the site of the attack.
"We have numerous witnesses to this," Sheahan said. "But what is the genesis of this? We don't know yet."