Alec Baldwin was under the impression the prop gun he was given on the set of the movie “Rust” was safe to use before the fatal shooting on Thursday that killed cinematographer Halyna Hutchins and injured director Joel Souza.

According to a Saturday report from CNN citing court documents, Baldwin was handed a prop gun on the film's New Mexico set by assistant director David Halls who yelled “cold gun.” The phrase alerts everyone that the weapon doesn’t have live rounds and is safe to use in a scene.

However, Hall was unaware the gun contained live rounds, the outlet reports. When Baldwin fired, Hutchins, 42, was hit in the chest, and Souza, 48, who was standing nearby, was wounded.

Prior to the shooting, some members of the crew walked off of the set due to the working conditions and safety concerns. A source told Deadline at least one previous incident involved “a misfiring of a weapon that was used days before in a scene.”

“A gun had two misfires in a closed cabin,” the insider explained. “They just fired loud pops — a person was just holding it in their hands and it went off.”

One source told the Los Angeles Times that Hutchins was advocating for safer working conditions before the fatal shooting. “Corners were being cut — and they brought in nonunion people so they could continue shooting,” the insider said.

Following the incident, Rust Movie Productions LLC announced the Western film would be paused indefinitely. 

“The entire cast and crew has been absolutely devastated by today’s tragedy, and we send our deepest condolences to Halyna's family and loved ones,” the production company said in a statement on Thursday evening. 

“We have halted production on the film for an undetermined period of time and are fully cooperating with the Santa Fe Police Department's investigation. We will be providing counseling services to everyone connected to the film as we work to process this awful event.”

Baldwin, who was a lead actor on the film and also serves as a producer, later tweeted that he was “fully cooperating with the police investigation to address how this tragedy occurred.”

Court documents show that investigators have seized all ammunition, firearms, computer equipment, cameras, and the clothes worn by actors when the shooting occurred.

Actor Alec Baldwin said he was "fully cooperating" with the police inquiry after he shot dead a cinematographer and wounded the director in an apparent accident involving a prop gun on a movie set Actor Alec Baldwin said he was "fully cooperating" with the police inquiry after he shot dead a cinematographer and wounded the director in an apparent accident involving a prop gun on a movie set Photo: AFP / Angela Weiss