The missing person was not alive by the time authorities reached them at the mangled Hard Rock Hotel construction site.
Video showed debris crash from several stories up, landing on cars in the street below.
Emergency crews evacuated nearby buildings as a precaution, given one of the two massive cranes was considered dangerously unstable.
Footage shot from the ground showed people fleeing the area as metal fell from the sky.
At least 18 people needed medical attention.
According to contractor Citadel Builders LLC, which employs people on the site, more than 100 people were working at the building when tragedy struck.
A spokesperson said the company was working with officials to figure out how to stabilize the building. The company didn’t comment on a possible cause of the collapse.
In a statement released by Hard Rock International, the company expressed sympathy to the victims, explaining they licensed the construction to a third party, Kailas Companies.
Information from The Associated Press contributed to this report.