The latest on the "Rust" movie set shooting investigation

Santa Fe County Sheriff Adan Mendoza said that "we suspect there were other live rounds that were found on set" of the "Rust" movie, where a shooting incident resulted in the death of director of photography Halyna Hutchins last week.

The sheriff said authorities are conducting further investigations to determine how crew members obtained a gun with a live round in it.

"The people that inspected or handled the firearm when it was loaded before it got to Mr. Baldwin — we're interviewing. And there [are] some followup questions that we need to do," he said.  

Later in the press conference, Mendoza said:

"We know there was one live round, as far as we're concerned, on set. We're going to determine whether we suspect that there were other live rounds, but that's up to the testing. But right now, we're going to determine how those got there, why they were there, because they shouldn't have been there."  

Authorities in New Mexico are conducting a “thorough and objective” investigation into what happened on the “Rust” set last week, but no charges have been filed yet in the death of Halyna Hutchins.

During a press conference Wednesday morning in Santa Fe, Adan Mendoza, Santa Fe County Sheriff, confirmed that Alec Baldwin fired the weapon. Baldwin, armorer Hannah Gutierrez and assistant director David Halls have been cooperative with investigators, according to Mendoza.

About 500 rounds of ammunition have been seized from the set, Mendoza said. He said they believe the spent shell casing from the bullet that was fired from the gun and a projectile was recovered from the shoulder of Joel Souza, the movie’s director who was also injured in the shooting. 

The evidence will be submitted to the FBI for further processing, he said. 

Mendoza said it’s too early to comment on possible charges.

Santa Fe District Attorney Mary Carmack-Altwies stressed that the investigation into the "Rust" shooting is still ongoing but said she is ready to "initiate prosecution" if needed.

"I must emphasize that a complete and thorough investigation is critical to the DA review. We take the corroborated facts and evidence and connect it to New Mexico law, and we are not at that juncture yet," she said, noting earlier that her office will "make sure this investigation will be held to the highest standards."

"I rely on facts supported by evidence, cooperative and credible witnesses, and I cannot stress the importance of allowing the Santa fe county sheriff's office to continue with their quality investigation that is both serious and complex," she added.

Santa Fe County Sheriff Adan Mendoza said earlier that its "too early" to comment on charges, but that the three people who handled the gun that was shot by actor Alec Baldwin are cooperating with the investigation.

Santa Fe County Sheriff Adan Mendoza said it's "too early" to comment on charges following the fatal shooting on the "Rust" set, but added arrests will be made if the investigation shows a crime occurred.

"It's too early right now in the investigation to comment on changes at this point," he said at a news conference.

He added:

The director of photography of "Rust," Halyna Hutchins, was killed last week as actor Alec Baldwin was practicing drawing a prop gun during rehearsals.

Baldwin has said he's cooperating with authorities.

In the first briefing since the fatal shooting on the "Rust" movie set Thursday, Santa Fe County Sherriff Adan Mendoza said investigators have collected 600 items of evidence, including what officials believe is the gun fired by actor Alec Baldwin.

"We have recovered what we believe to be possible, additional live rounds on set," Mendoza said, adding, "All the previous mentioned items, along with other items of evidence, will be submitted to the FBI crime lab in Quantico, Virginia, for analysis."

Santa Fe County Sheriff Adan Mendoza and Santa Fe District Attorney Mary Carmack-Altwies are holding a joint news conference soon to discuss the ongoing investigation into the shooting incident on movie set “Rust.”

A district attorney spokesperson confirmed to CNN that Carmack-Altwies is not ruling out criminal charges in the fatal shooting, noting that the incident remains under active investigation. 

In an interview with the New York Times, Carmack-Altwies said the term “prop gun” is misleading and that the gun that killed Halyna Hutchins was a “legit gun,” describing it as an “antique-era appropriate gun.”

According to the report, Carmack-Altwies said the investigation is focusing on ballistics to determine what kind of rounds were used, and who placed them in the gun fired by actor Alec Baldwin.

What we know so far about the investigation: Investigators also found two other prop guns, a Western-style gun belt and some ammunition. In the affidavit, detectives sought a search warrant to seize more items as evidence, including firearms and ammunition, cameras, memory cards and computers.

The Bonanza Creek Ranch, which has been used for dozens of Western-themed movies and TV series, including "Lonesome Dove" and "Cowboys and Aliens," now sits deserted. The production team said it has halted filming on "Rust," at least until the investigation into the shooting is complete.

CNN's Josh Campbell and Faith Karimi contributed reporting to this post.

Neal Zoromski, a long time Hollywood prop master, declined an offer to work on “Rust” after being asked by producers to fulfill two roles on the movie set, an approach that he thought was “flawed.”

Zoromski said he was asked to take on two jobs, one as an armorer and another as an assistant key prop master.

Zoromski explained that, “if you are loading a gun, you’re right up next to the camera. If you’re an assistant key prop master, then you are in the background loading the wagons, checking the bridles, making sure the trunk is being loaded and offloaded and repeated over and over again.”

“There are so many things that go on in between the foreground and the background and to have to cover that amount of territory, and to do it well, is challenging for even a seasoned professional,” he added. 

Zoromski said he had misgivings about the job as he spoke to various people on the production team about numbers, budgeting, and staffing questions that needed to be addressed.

“We were in the process of negotiating over several days, we had sort of been up and down with numbers and staffing numbers,” Zoromski said.

Zoromski said he expressed his concerns and needs during the negotiation but they were not immediately addressed when presented to producers and staff. 

A law firm has been hired by “Rust” producers to investigate the shooting that killed the film's director of photography Halyna Hutchins and injured director Joel Souza, Deadline.com reported exclusively.

CNN has not received a copy of the letter that Deadline said was distributed to cast and crew members. CNN has reached out to law firm Jenner & Block for comment.

Today, the district attorney and the Santa Fe Sheriff’s Office are expected to hold a news conference to provide an update on the investigation. 

Attorney Gloria Allred says her client, “Rust” script supervisor Mamie Mitchell, has evidence which will be “helpful in this investigation” and has been interviewed by law enforcement.

In a statement, Allred said Mitchell was standing near Halyna Hutchins and director Joel Souza when they were shot and immediately ran out of the church. 

They believe she was the first person to call 911.

Allred described her client as “traumatized” and said they are conducting their own investigation into what happened.

Hutchins was killed on set when actor and producer Alec Baldwin discharged a prop firearm last Thursday.