An updated search warrant from the Santa Fe County Sheriff's Office gives new details about the fatal shooting on the set of Rust that killed cinematographer Halyna Hutchins.
Dave Halls, the assistant director who handed Alec Baldwin the firearm with which he shot Hutchins and director Joel Souza, admitted to authorities that there was a lapse in gun safety protocol on set leading up to the incident, according to the search warrant obtained by the New York Post.
Explaining the typical protocol, Halls told deputies: "I check the barrel for obstructions, most of the time there's no live fire, she (armorer Hannah Gutierrez-Reed) opens the hatch and spins the drum, and I say cold gun on set," according to the warrant.
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On the day of the incident, Halls said that Gutierrez-Reed showed him the loaded firearm after the crew returned from lunch, so that they could continue rehearsals. He told authorities he could only remember seeing three rounds in the gun, the affidavit states.
According to the warrant, he admitted that he should have checked each round, but he did not. He couldn't remember if Gutierrez-Reed spun the drum.
After the incident, Halls picked up the gun from a church pew on set and took it to Gutierrez-Reed, instructing her to open it so he could see what was inside. When the armorer opened the gun, Halls told authorities he saw five rounds in the gun — four "dummy" rounds, indicated by a hole in the casing, and one "without the hole," according to the warrant.
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He also advised that the round without the hole didn't have a "cap" on it, and "was just the casing." He maintained that the shooting was "not a deliberate act," the warrant states.
In her interview with deputies, Gutierrez-Reed said that she had checked the rounds inside the firearm to make sure they were "dummies," and not real bullets. When the crew broke for lunch, the guns were locked inside a safe on the prop truck, which few people had access to, she added.
Gutierrez-Reed also told authorities that no live ammunition was ever kept on set, according to the affidavit.
On Wednesday, New Mexico authorities confirmed that the projectile that killed Hutchins and injured Souza was a real lead bullet.
According to a preliminary investigation, the bullet, which was accidentally fired by actor Alec Baldwin Thursday, fatally struck Hutchins before hitting Souza, Santa Fe County Sheriff's Office spokesperson Juan Rios tells PEOPLE.
It has since been recovered from Souza's shoulder.
At a press conference, Sheriff Adan Mendoza said investigators discovered "500 rounds of ammunition" on the set, including, "a mix of blanks, dummy rounds and what we are suspecting are live rounds."
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Rios confirmed to PEOPLE afterward that "live rounds" means "real bullets."
It's unclear where the bullets came from. Mendoza told reporters Wednesday he believed "there was some complacency on this set."
Following Mendoza's comments Wednesday, Santa Fe District Attorney Mary Carmack-Altwies echoed that in terms of criminal charges against Baldwin or others, "all options are on the table at this point" and "no one has been ruled out" as they search for answers as to what led to the fatal shooting on the set of the Western film.
The investigation remains ongoing, with production on the film halted. No charges have been filed.
Neither Halls nor Gutierrez-Reed have spoken publicly about the incident.