File video above: Legal analysis on charges filed against Alec Baldwin on 'Rust' movie set shooting

Prosecutors in the "Rust" fatal shooting case plan to file a notice to dismiss involuntary manslaughter charges against Alec Baldwin, his attorney, Luke Nikas, tells CNN.

CNN has contacted the special prosecutor in the Santa Fe, New Mexico case for comment.

Halyna Hutchins, the film's cinematographer, was struck and killed by a live round of ammunition fired from a prop gun being held by Baldwin while rehearsing a scene on the set of "Rust" in 2021. Baldwin has pleaded not guilty.

Director Joel Souza was also shot and injured.

Baldwin and "Rust" armorer Hannah Gutierrez Reed were both charged with involuntary manslaughter in January. Baldwin pleaded not guilty. An attorney for Gutierrez Reed has previously said she will plead not guilty and has maintained her innocence. A preliminary hearing in her case is set for May 3.

Prosecutors already removed a firearm enhancement charge against Baldwin and Gutierrez Reed, reducing a potential prison sentence from 5 years to a maximum of 18 months.

"We are pleased with the decision to dismiss the case against Alec Baldwin and encourage a proper investigation into the facts and circumstances of this tragic accident," Baldwin's attorneys Luke Nikas and Alex Spiro told CNN.

Thursday's development comes one month after the special prosecutor in the case, Andrea Reeb, stepped down, following a motion by Baldwin's attorney to have Reeb disqualified as "unconstitutional" under New Mexico law due to her elected position in the New Mexico House of Representatives. Santa Fe District Attorney Mary Carmack-Altwies then also stepped away from the case and appointed long-time New Mexico attorneys Kari Morrissey and Jason Lewis to serve as special prosecutors.

Earlier this year, "Rust" assistant director Dave Halls and prosecutors reached a plea agreement "for the charge of negligent use of a deadly weapon." At the time, prosecutors said the terms of that deal include six months of probation and a suspended sentence.

As part of a wrongful death settlement between Matthew Hutchins, the widower of Halyna Hutchins, Baldwin and "Rust" producers, production on the film has resumed. Matthew Hutchins is now serving as an executive producer on the project.

LOS ANGELES (AP) — The husband of a cinematographer shot and killed on the set of the film "Rust" says it's "absurd" that Alec Baldwin believes he's not to blame.

Matt Hutchins, the husband of Halyna Hutchins, made the remarks in an interview with the "Today" show that airs in full Thursday.

In the interview with Hoda Kotb, Hutchins said Baldwin and “multiple responsible parties” are to blame for his wife of 16 years' death.

Matt Hutchins says he was "so angry" when he heard Baldwin tell ABC News in December that he was not to blame for the shooting.

Baldwin said he was pointing the gun at Hutchins at her instruction as a scene was being set up on the New Mexico set, and it went off without him pulling the trigger.

In his interview with George Stephanopoulos, Baldwin said that he did not pull the trigger. He claimed he cocked the hammer, let the hammer go, and the gun went off.

Director Joel Souza, who was standing behind Hutchins, was injured in the Oct. 21 shooting.

Last week, Hutchins' family filed a wrongful death lawsuit in New Mexico alleging Baldwin, the production's assistant director Dave Halls, prop master Hannah Gutierrez-Reed and others that their “reckless" behavior resulted in her death.

Cinematographer Halyna Hutchins died Thursday after a prop firearm that actor Alec Baldwin was holding discharged on the New Mexico set of "Rust." Director Joel Souza was also hit and injured but has since been released from the hospital. While many things still aren't known — police are investigating — the AP looks at the use of firearms on film and television productions and the safety protocols in place.

WHAT IS A "PROP FIREARM"?

It's a loose definition and could apply to anything from a rubber toy to a real firearm that can fire a projectile. However, if it's used for firing (even just blanks) it's considered a real gun. Chris Burbank, a former police chief in Salt Lake City who has consulted on several TV productions, said firearms for simulations during police trainings or film productions are often made so that they can only be loaded with blanks.

WHAT ARE BLANKS AND CAN THEY KILL?

A blank is a type of gun cartridge that contains gunpowder but no bullet. Still, it can serious hurt or kill someone who is close by, according to the Actors' Equity Association. Film firearms-safety coordinator Dave Brown wrote in a 2019 piece for American Cinematographer that, "Blanks expel gunpowder and hot gases out of the front of the barrel in a cone shape. This is harmless at longer ranges, but the explosion can seriously injure someone if it's too close."

IN THIS INSTANCE, WERE BLANKS FIRED?

We don't know. The Santa Fe County Sheriff's Office is investigating what "type of projectile was discharged."

WHO IS RESPONSIBLE FOR THE WEAPONS ON SET?

Generally, a weapons master or armorer oversees all weapons that are used on a production. This can mean anything from selecting the correct items for a certain period in history, to taking care of the weapons on set and making sure they are being used safely and properly by actors and stuntpeople. It's a fairly new position in the history of film production, going back only to the 1980s. Before that, the prop master handled everything. Recently, it's become more common to enlist specialists.

WHAT ARE THE RULES FOR FIREARMS ON SET?

The weapons master is required to be on set whenever a weapon is being used. The Actors' Equity Association's guidelines state that, "Before each use, make sure the gun has been test-fired off stage and then ask to test fire it yourself. Watch the prop master check the cylinders and barrel to be sure no foreign object or dummy bullet has become lodged inside." Further, "All loading of firearms must be done by the property master, armorer or experienced persons working under their direct supervision."

Armory coordinator Sam Dormer said that, "Nowadays, all weapons are checked before your blanks are put into the weapon. ... The blanks themselves are never loaded until the very last minute when all crew is in position, so the armorer knows exactly where every member of the crew is so that no one's walking through any danger areas the armorer has set up."

HOW DOES ONE BECOME A WEAPONS MASTER?

According to Backstage magazine, there's no formal path but it is common to have internships and apprenticeships or a background in stunt work, the military, police or security. Weapons masters are required to abide by state and federal laws and hold proper operating permits.

WHY WOULD THE GUN HAVE BEEN POINTING AT THE CINEMATOGRAPHER?

We don't know what happened on the set of "Rust," but it is fairly common to have a gun pointed at the camera, and by extension the cinematographer, to get a certain angle.

"We've all seen the very famous shots in films where you get that dramatic effect of a gun being pointed at you, the audience, and of course, it's being pointed towards the camera," explained Steven Hall, a veteran second unit director and cinematographer who has worked on films like "Fury" and "Thor: The Dark World." "To minimize that, one would put a remote camera in that place, or at least if someone does have to operate the camera, I'm normally protected by safety goggles, a safety visor and often a PERSPEX screen that withstands pretty much anything. Obviously, it wouldn't withstand a real shot from a gun, but it would certainly withstand a blank."

GIVEN THE MANY REGULATIONS, HOW COULD SOMETHING LIKE THIS HAPPEN?

While the specific circumstances of the "Rust" shooting are still unknown, professionals in the business say that sometimes the crew and production are encouraged to "speed things up" for any number of reasons which can sometimes lead to "relaxed" safety protocols.

DOES IT MAKE IT MORE COMPLICATED WHEN IT'S A PERIOD PIECE?

"Rust" is set in the 1880s and according to Hall, when period weapons are used "you have to use actual historic period weapons and to check the safety of those weapons. I have known live rounds to be fired out of revolvers, certainly, to make sure that they do function in a way that when you put a blank in, it isn't going to blow up or explode in the actor's hands."

WHY DO PRODUCTIONS EVEN USE REAL GUNFIRE WHEN SPECIAL EFFECTS ARE AVAILABLE?

It is becoming more common to add in gunfire in post-production when working on the visual effects. But visual effects can be expensive and it can be easier, and cheaper, to use props. Also, Dormer says that there can be advantages to using props and blanks, like getting an authentic reaction from an actor.

HOW IS HOLLYWOOD RESPONDING?

There has been an outpouring of dismay and anger from all levels of the industry that something like this could have happened. Director James Gunn tweeted that his greatest fear is that "someone will be fatally hurt on one of my sets." Alex Winter tweeted that, "Crew should never be unsafe on set and when they are there is always a clearly definable reason why."

AP reporters Lizzie Knight and Adam Egan contributed from London and Lindsay Whitehurst from Salt Lake City.