Authorities found 12 revolvers and a '.45 Colt round' in a prop truck on the set of 'Rust'

• Authorities discovered multiple firearms in a prop truck on the set of "Rust," according to new documents obtained by Insider.
• The search warrant confirmed that 12 revolvers, a rifle, and a ".45 Colt round" were in the truck.

Authorities discovered more than a dozen firearms as well as a revolver round in a prop truck on the New Mexico set of "Rust," according to a newly released court document.

An inventory obtained by Insider showing the results of a search warrant states there were 12 revolvers, a rifle, and a ".45 Colt round" in a white "prop" truck on the set.

It's unclear if the round was a live bullet or a blank.

Alec Baldwin fired a gun that killed the film's cinematographer Halyna Hutchins and injured director Joel Souza while rehearsing for a scene for the upcoming film on October 21.

Santa Fe sheriffs said the gun had been loaded with an apparent live lead bullet.

Assistant Director Dave Halls told police that he did not check all the rounds in the barrel before declaring the gun was "cold" - meaning it wasn't loaded with a live bullet - and handing it to Baldwin.

"I check the barrel for obstructions, most of the time there is no live fire," Halls told Santa Fe investigators, according to the affidavit. He later recalled seeing at least four harmless "dummy" rounds in the gun along with an apparently fired bullet.

Hannah Gutierrez-Reed, the armorer on set, said in a statement that she had "no idea where the live rounds came from."

"Rust" has since paused production and the investigation into the incident continues.

Halls did not respond to an Insider request for comment on Wednesday.