A Call of ‘Cold Gun!’ A Live Round. And Death on a Film Set.

SANTA FE, N.M — Alec Baldwin was on the set of his latest film, a low-budget western called “Rust,” working on a scene in which his character, a grizzled outlaw named Harland Rust, finds himself in a small wooden church, cornered by a sheriff and a U.S. Marshal, and decides to shoot his way out.

Members of the small crew — including the director, cinematographer, cameraman and script supervisor — clustered around Mr. Baldwin inside the cramped, spartan set. The location is on a sprawling ranch outside Santa Fe, where Hollywood has been sending some of its biggest actors to don Stetsons and leather holsters to film westerns since 1955, when Jimmy Stewart made “The Man From Laramie” there.

As light poured through the church’s windows, casting slanted rays in the dust that swirled over the pews, a shadow fell, and the crew had to adjust the camera angle.

Then it was time for Mr. Baldwin, 63, who was seated on a pew, to practice his scene: a close-up of his hand as he slowly reached across his chest, drew a .45 Long Colt revolver from a shoulder holster and moved it toward the lens of the camera. The crew had been assured the gun was “cold,” meaning it held no live ammunition, according to court papers. In fact, investigators said, it was loaded with a live round. The error would prove fatal.

Suddenly there was a loud noise that the director, Joel Souza, later told a detective “sounded like a whip and then loud pop” as the gun went off.

The film’s cinematographer, Halyna Hutchins, 42, who was standing just feet away from Mr. Baldwin, to the left of the camera, grabbed her midsection and began to stumble backward, fatally struck in the chest by a lead bullet that investigators say passed through her and then wounded the film’s director, Mr. Souza, 48.

The questions of why there was any live ammunition on a movie set, where it is usually forbidden, and how a revolver loaded with a lethal round was placed in the hands of an actor, have started a complicated inquiry as law enforcement officials in New Mexico try to determine whether negligence on the set of “Rust” rose to the level of a crime. It has raised questions about firearm safety on sets, and whether proper procedures were followed on “Rust,” a troubled production where some members of the crew had quit before the shooting.

Those core questions about the gun and ammunition remain unanswered. But a reconstruction of the events based on court papers and interviews with members of the production, crew and law enforcement officials makes it clear that a cascading series of mistakes led to the fatal moment just before 1:48 p.m. on Oct. 21.

A Delayed Start, After Trouble on the Set

The “Rust” crew started work before dawn, at about 6:30 a.m., and the crew gathered for breakfast at Bonanza Creek Ranch, where the movie was being filmed.

But a major problem had emerged the night before: Six members of the camera crew had sent in resignation letters, citing issues including a lack of hotel accommodations and late paychecks.

The tensions on the set came amid a broader national labor battle over working conditions in the industry. As “Rust” went into its second week of work on location in mid-October, the union that represents members of film crews was negotiating a new contract with production studios.The union, the International Alliance of Theatrical Stage Employees, voted this month to authorize a nationwide strike if talks failed.

Mr. Baldwin had arrived on the set about a week after filming had started in early October, and had spent time working on his horseback riding, rehearsing scenes and practicing with guns, including trying to simulate the recoil that is missing when live rounds are not used.

Mr. Baldwin was not only the star of the film, which was expected to cost about $6.5 million to make, but one of its producers, along with Ryan Winterstern, Matt DelPiano, Anjul Nigam, Ryan Donnell Smith and Nathan Klingher.

After the union’s leaders reached a tentative agreement with the studios, Mr. Baldwin posted an Instagram video — filmed from Santa Fe — in which he urged the rank-and-file members to strike if they were unhappy with the deal.

Tensions on the set of “Rust” were building, though. And just days before the fatal shooting, at least two accidental gun discharges on set had put crew members on edge.

One former member of the “Rust” crew said in an interview that he had been alarmed by the safety conditions on the production. “It was the most unorganized set I’ve ever seen,” said the crew member, who was granted anonymity because he feared that speaking out would harm his future work prospects.

He said there had been concern about the limited experience of the film’s armorer, who was in charge of the weaponry on the set: Hannah Gutierrez-Reed, who was 24 years old and just starting her career as a head armorer.

Ms. Gutierrez-Reed’s lawyers, Jason Bowles and Robert Gorence, said in a statement Friday that Ms. Gutierrez-Reed was working two different jobs on the film, “which made it extremely difficult to focus on her job as an armorer.’’ (The production did not immediately respond to a request for comment on the statement.)

The lawyers charged that “the whole production set became unsafe due to various factors, including lack of safety meetings,” and suggested that others had been responsible for previous accidental discharges on the set: “The first one on this set was the prop master, and the second was a stunt man after Hannah informed him his gun was hot with blanks.”

Even as the tensions brewed, one former “Rust” crew member said, Ms. Hutchins, the cinematographer, bonded with members of the crew, taking some out for sushi after a long day of work.

“She was very passionate about what we were all doing,” he recalled.

Ms. Hutchins told a friend, Dan Frenkel, over the phone that there were labor tensions but that she thought they could work through them.

They could not. Most of the film’s camera crew resigned over issues that were not dissimilar to those that union leaders had been discussing at the bargaining table.

A Live Round Goes Undetected in Safety Check

The production had been delayed, but replacement crew members were found, and the crew got back to work.

They were working on the church scene when, at about 12:30 p.m., it was time for lunch. Production workers were shuttled in vans to a nearby catering tent. The guns and some ammunition were kept locked in a safe kept inside a white truck, but some ammunition remained unsecured on a cart outside.

After lunch, the film’s prop master, Sarah Zachry, entered the combination to the safe and handed the guns to Ms. Gutierrez-Reed, who set them up on a gray cart outside the church.

Both Ms. Gutierrez-Reed and Dave Halls, the first assistant director, were supposed to check the guns before handing them to actors.

The protocol, Mr. Halls told a detective, was for Ms. Gutierrez-Reed to show him the gun so he could check its barrel for obstructions, and for her to then open the revolver and spin it so he could see the contents of its chambers. Then he would call out “cold gun,” signaling to the crew that the gun did not contain live rounds.

When the cast and crew got back from lunch that day, Ms. Gutierrez-Reed showed Mr. Halls the .45 Colt revolver that Mr. Baldwin would handle. Mr. Halls told a detective that he recalled seeing three rounds inside but could not recall whether Ms. Gutierrez-Reed had spun the drum so he could check every chamber and every round.

“He advised he should have checked all of them, but didn’t,” Detective Alexandria Hancock wrote.

Both Ms. Gutierrez-Reed and Mr. Halls have been the subjects of complaints on previous productions.

In 2019 Mr. Halls was fired from a movie, “Freedom’s Path,” after a gun discharged unexpectedly on set, causing a minor injury to a crew member, its production company said. Neither Mr. Halls nor his lawyers responded to requests for comment.

Ms. Gutierrez-Reed, who had been learning how to be an armorer from her father, Thell Reed, a Hollywood weapons expert, was just getting started as a head armorer herself. In a recent podcast, she noted that she had just finished filming her first movie as head armorer, a western called “The Old Way” starring Nicolas Cage, and confided that “I almost didn’t take the job because I wasn’t sure if I was ready.”

Stu Brumbaugh, a key grip on “The Old Way,” said in an interview that he had recommended Ms. Gutierrez-Reed be fired after he witnessed two unannounced discharges of weapons she was holding, startling others and in one case prompting an angry reaction from Mr. Cage. She was kept on, he said, which he saw as evidence of a broader problem in which producers try to cut costs by hiring less experienced crews. The incident was reported earlier by CNN.

Lawyers for Ms. Gutierrez-Reed said that she had “never had an accidental discharge” during her career; they did not respond to follow-up questions about the incident on “The Old Way.”

“Ultimately this set would never have been compromised if live ammo were not introduced,” her lawyers said of the “Rust” set. “Hannah has no idea where the live rounds came from.”

A “Cold Gun” That Was Anything But

“Cold gun!” Mr. Halls called out after lunch as he handed the revolver to Mr. Baldwin.

Then, as Mr. Baldwin practiced his draw, the gun went off.

Ms. Hutchins stumbled backward and was helped to the ground. Mr. Souza saw blood on her — and then noticed that he was bleeding, too. Ms. Hutchins said she could not feel her legs.

Mamie Mitchell, the movie’s script supervisor, ran out of the church, cellphone in hand, and dialed 911.

“We’ve had two people accidentally shot on a movie set by a prop gun,” Ms. Mitchell told the dispatcher. “We need help immediately.”

At 1:48 p.m., the sheriff’s department was dispatched to the ranch.

Back on the set, Mr. Halls picked up the revolver from a church pew and handed it to Ms. Gutierrez-Reed, who opened it up to see what was inside. Mr. Halls told a detective that he saw at least four rounds with a hole in the side, which sometimes indicate that a round is a dummy. (Dummy rounds contain no gunpowder and are used to resemble bullets on camera.)

But there was another round in the gun, he told a detective, one with just a casing, no cap, and which did not have the pierced hole.

Real sheriff’s deputies, from Santa Fe County, rushed to the church set, with the first arriving at 2 p.m. Ms. Hutchins was flown by helicopter to a hospital in Albuquerque, where she was pronounced dead. Mr. Souza was taken to a closer hospital.

Mr. Baldwin’s western costume was turned over for evidence, because it appeared to be stained with blood.

A few days later, Sheriff Adan Mendoza of Santa Fe County would announce what had become increasingly clear: The gun had fired a live round, a lead bullet.

The bullet was recovered from the director’s shoulder. Now the investigation is focused on how it got into the revolver.

Simon Romero reported from Santa Fe, Julia Jacobs from New York and Graham Bowley from Toronto. Nicole Sperling contributed reporting.