Ever since, investigators have been poring over what went wrong on the movie set.
So what did they reveal in their latest update on the case - and who was Halyna Hutchins?
Here’s what you need to know.
What happened on the set of Rust?
Alec Baldwin, star of films including Mission Impossible, The Departed and Glengarry Glen Ross, fatally shot Halyna Hutchins while starring in the title role of the film Rust.
Local police said deputies were dispatched to Bonanza Creek Ranch - a popular filming location - just before 2pm local time (8pm GMT) on 21 October after receiving an emergency call about a shooting on set.
Ms Hutchins, 42, was taken to hospital but died of her injuries.
The film’s director, Joel Souza, 48, was injured in the shoulder by the bullet that killed Ms Hutchins as he was standing directly behind her.
After receiving emergency care he was discharged from hospital.
Alec Baldwin was questioned by police on the day of the incident, with local newspaper the Santa Fe New Mexican reporting he was seen outside the sheriff’s office in tears.
In a statement on his arts foundation’s social media account, Mr Baldwin wrote: “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.
“I’m fully co-operating with the police investigation to address how this tragedy occurred and I am in touch with her husband, offering my support to him and his family.
“My heart is broken for her husband, their son, and all who knew and loved Halyna.”
What did the police say in their update?
In an update on Wednesday 27 October, the Santa Fe county sheriff Adan Mendoza revealed a “lead projectile” believed to have been fired from the gun, had been recovered.
It was taken out of Mr Souza’s shoulder.
The projectile, “apparently the same round” that proved fatal for Ms Hutchins, is suspected to be a live round.
But Mr Mendoza said that would not be confirmed until it undergoes further testing.
About 500 rounds of ammunition have been recovered from the set, the sheriff said. These are thought to include dummies, blanks and suspected live rounds.
FBI experts will make the final determination but the sheriff said he suspects more live rounds will be confirmed.
The sheriff refused to speculate on how they could have come to be found on the set and added it was still too early to say if criminal charges will be filed.
There was “some complacency” on the set, he said, but it is yet to be determined if there was negligence or by whom.
Two people handled the revolver, described as an “antique era-appropriate gun”, before it was handed to Baldwin, Mr Mendoza said.
They were armourer Hannah Gutierrez-Reed and assistant director David Halls, according to the authorities.
They and Baldwin have been cooperative, the sheriff stressed.
According to a newly released search warrant, Gutierrez-Reed said she had checked the dummy rounds before the shooting to ensure they were not live.
She told police guns used for filming were locked up during a crew lunch break but ammunition was left unsecured.
Following the shooting, Halls said he checked the gun and saw at least four of the five rounds were dummy bullets.
But a casing in the firearm did not have a cap to indicate it was a dummy, according to the warrant.
An assistant director handed Mr Baldwin the firearm and shouted “cold gun”, indicating it was safe, court records show.
Regardless of whether there are criminal charges, experts believe there will be a significant legal fallout from Ms Hutchins’ death.
Who was Halyna Hutchins?
Halyna Hutchins, who died in the incident involving Mr Baldwin, was a cinematographer.
According to Ms Hutchins’ personal website, she was originally from Ukraine and grew up on a Soviet military base in the Arctic Circle.
She had studied international journalism at Kyiv National University and had previously worked as an investigative journalist on British documentary productions in Europe.
In 2015, Ms Hutchins graduated from the AFI conservatory - a Los Angeles film school - and had worked on dozens of film projects since.
Halyna was selected as one of American Cinematographer’s Rising Stars of 2019.
Her recent projects included 2020 feature film Archenemy, which was directed by Adam Egypt Mortimer and starred Joe Manganiello and Skylan Brooks.
Posting on Twitter, Mr Mortimer said he was “so sad” at losing Halyna and that he “was lucky to have known her and to have worked with her”.
In a statement, the International Cinematographer’s Guild said Ms Hutchins’ death was "devastating news" and "a terrible loss".
Guild president John Lindley and executive director Rebecca Rhine said: "The details are unclear at this moment, but we are working to learn more, and we support a full investigation into this tragic event.”
What is ‘Rust’ about?
The movie Halyna Hutchins was filming with Alec Baldwin would have been her most major credit to date.
Set in the US in the 1880s, the film is about a 13 year-old boy who goes on the run with his estranged grandfather - Mr Baldwin - after he’s sentenced to hang for the accidental killing of a local rancher.
Alongside Baldwin, the film’s other star is Vikings actor Travis Fimmel.
Production on Rust has been paused and it is unclear whether filming will resume.
Additional reporting by PA
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