The prop gun used in the fatal shooting of the cinematographer of the movie Alec Baldwin was producing had misfired before on the set, sources familiar with the situation told NBC News Friday.
Just a few hours before Baldwin fired the shot that killed the highly regarded cinematographer, Halyna Hutchins, and also wounded the director, Joel Souza, several members of the crew walked off the set of “Rust” because of safety concerns, the sources said.
The disclosure came as investigators probing the tragedy at the Bonanza Ranch in New Mexico were seeking to question the three workers who were supposed to make sure Baldwin was firing blanks, sources said.
Alec Baldwin discharged prop gun in deadly accident on film setOct. 22, 202103:21
The production company said in a statement Friday that the "safety of our cast and crew is the top priority of Rust Productions and everyone associated with the company. Though we were not made aware of any official complaints concerning weapon or prop safety on set, we will be conducting an internal review of our procedures while production is shut down."
The workers based in and around Albuquerque appeared to have ties to the local film industry before they were hired to work on Baldwin’s western, records show.
Their names were listed on the call sheet for Thursday, the day of fatal shooting, which NBC News obtained from one of the entities cooperating with police.
NBC News is withholding their names because police have not characterized the investigation into the deadly incident outside Santa Fe as an accident investigation or a criminal probe.
But those listed on the call sheets as the “property master, property key assistant/armorer, and property assistant” all bear the responsibility of making sure the weapons used in the movie are secure and safe to use, experts said.
Property masters, especially the armorers, on big movie sets are generally very experienced, but “Rust” was a low-budget movie, said Tobey Bayes, business agent for IATSE Local 44 in Hollywood, which is the 7,000-member property masters union.
So it was not immediately clear just how much experience these three crew members have and none of them are listed as members of Local 44, Bayes added.
Tim Barrera, whose job as second assistant director on “Rust” is to prepare the daily call sheets for the production schedule, said he did not know anything about the property masters who were on the set Thursday.
“I’m not in charge of the hiring process,” he said.
As for the death on the set, Barrera said “everything that I could say at this point would be speculation. The is an ongoing investigation and I’m going to leave it at that.”
There are strict protocols for how potentially lethal weapons are handled on movie sets, but the question of whether those were being followed when Hutchins was shot continues to be part of the police investigation.
Hutchins' death has already sent shockwaves through Hollywood and earlier Friday Baldwin tweeted that his "heart is broken" and that he is cooperating with investigators. But it also raised fresh questions about whether this set was safe.
The Los Angeles Times, citing sources, was the first to report Friday that there were two misfires of a prop gun on Saturday and that six hours before the fatal shooting union camera operators and their assistants walked off the job to protest working conditions.
“I am totally astonished this happened, especially with an experienced actor like Alec Baldwin,” said retired property master Christopher Amy, whose résumé includes work on television shows like “Dexter” and movies like “National Treasure” and “Lethal Weapon 4.”
Weapons used on movie and TV sets are kept in safes and the number of people who handle them are kept to a minimum, Amy said.
Six-shooters are generally the weapons of choice in westerns, but the ones used in the movies are adapted to fire blanks instead of live rounds that contain bullets. Blanks just have the gunpowder and hot gas.
Even so, before they’re handed to the actors the gun barrels are checked to make sure there is no bullet inside as are the revolving cylinders, Amy said.
“We never have live ammunition on the premises,” said Amy.
Then, before the filming is started, the crew dons protective face and ear coverings and nobody pulls a trigger until a signal is given, said Amy.
That’s because the industry-wide recommendation is that all weapons be treated as if they were loaded with live ammunition.
“Blanks can kill,” the guidelines say.
For Amy, the fatal shooting of Hutchins reminded him of the death of actor Brandon Lee, who was killed in 1993 while filming “The Crow” when he was shot with a real gun that was loaded with improperly made dummy rounds.
"We still don't really know what happened in New Mexico, but when I heard about the shooting I immediately thought of Brandon Lee," said Amy.
This story first appeared on NBCNews.com.