Alec Baldwin didn't know the prop gun that he fired was loaded with live ammunition and neither did the assistant director who handed it to him before the fatal shooting of a cinematographer on a New Mexico film set Thursday, a search warrant document says.
The assistant director yelled "cold gun" before the shooting that killed Halyna Hutchins, 42, and wounded director Joel Souza on the set of "Rust" at Bonanza Creek Ranch, according to an affidavit filed in a Santa Fe court.
The term "cold gun" is intended to indicate that the weapon did not have any live rounds, according to the document obtained by NBC affiliate KOB of Albuquerque and other news outlets.
The assistant director did not know live rounds were in the prop gun, the Santa Fe County sheriff's detective wrote in the court document. It was one of three prop guns on a cart that had been set up by an armorer, it said.
The assistant director did not immediately respond to a request for comment Friday, nor did the armorer.
Baldwin, 63, on Friday said that he was heartbroken and fully cooperating in the investigation.
"There are no words to convey my shock and sadness regarding the tragic accident that took the life of Halyna Hutchins, a wife, mother and deeply admired colleague of ours," Baldwin tweeted.
No charges have been filed in the case.
The search warrant document was filed as authorities sought to gather video, photos, firearms, clothing and other evidence. First Judicial District Attorney Mary Carmack-Altwies said Friday the case is still in its preliminary state of investigation.
Audio released Friday from a 911 call shows someone reported that two people had been shot by a prop gun on the set.
"We were rehearsing, and it went off and I ran out. We all ran out," the caller says. "They were doubled over — the AD and the camerawoman, and the director."
Hutchins was flown by helicopter to University of New Mexico Hospital, where she was pronounced dead. Souza was taken by ambulance to a hospital and has since been released.
The search warrant document says that Hutchins was shot in the chest and Souza, who was struck in the shoulder, was behind her.
The on-set shooting has prompted at least one other production to end the use of weapons that could potentially carry live ammunition.
The showrunner of the ABC police drama "The Rookie" said it will no longer use "live" weapons— instead using airsoft guns and adding the muzzle flashes with computers later. Airsoft guns fire plastic pellets.
"Any risk is too much risk," showrunner Alexi Hawley wrote in a memo to staff, the contents of which were confirmed by network representatives.
This story first appeared on NBCNews.com.