A New Mexico prosecutor on Wednesday said Alec Baldwin broke "cardinal rules" of gun safety in the 2021 killing of "Rust" cinematographer Halyna Hutchins while his lawyer said he was failed by firearms experts.

The 66-year-old Baldwin, on trial in Hollywood's first on-set shooting fatality in three decades, took notes at the defense table and listened calmly to opening statements in his involuntary manslaughter trial. The trial is largely unprecedented in U.S. history, holding an actor criminally responsible for a gun death during filming.

A New Mexico jury of 12 and four alternates — 11 women and five men — heard prosecutor Erlinda Johnson outline arguments that Baldwin disregarded safety during filming of the low-budget movie before pointing a gun at Hutchins during a rehearsal, cocking it and pulling the trigger as they set up a camera shot on a set southwest of Santa Fe.

"The evidence will show that someone who played make believe with a real gun and violated the cardinal rules of firearm safety is the defendant, Alexander Baldwin," Johnson said.

Baldwin's wife Hilaria Baldwin sat in the second row of the public gallery, his brother Stephen Baldwin in front of her.

His lawyer Alex Spiro pointed to "Rust" armorer Hannah Gutierrez — head of gun safety — and first assistant director Dave Halls — responsible for overall set safety. Both have been convicted in the shooting, and Spiro said they did not check the rounds in the gun to ensure it was safe for Baldwin to use.

"There were people responsible for firearms safety but actor Alec Baldwin committed no crime," said Spiro.

Hutchins was killed, and director Joel Souza wounded when Baldwin's reproduction 1873 Single Action Army revolver fired a live round, inadvertently loaded by Gutierrez.

Since a police interview on Oct. 21, 2021, the day of the shooting, Baldwin has argued the gun just "went off."

In an ABC News interview two months later, Baldwin told George Stephanopoulos he did not pull the trigger. A 2022 FBI test found the gun was in normal working condition and would not fire from full cock without the trigger being pulled.

Spiro said during his opening arguments that no one saw Baldwin "intentionally pull the trigger," but that it was the responsibility of firearms safety experts to ensure a firearm was safe for an actor "to wave it, to point it, to pull the trigger, like actors do."

State prosecutors charged Baldwin with involuntary manslaughter in January 2022. They dropped charges three months later after Baldwin's lawyers presented photographic evidence the gun was modified, arguing it would fire more easily, bolstering the actor's accidental discharge argument.

Prosecutors called a grand jury to reinstate the charge in January after an independent firearms expert confirmed the 2022 FBI study.

FBI testing broke the gun, and Baldwin's lawyers will tell jurors that destruction of the weapon prevented them from proving the gun was modified.

Armorer Gutierrez, whose job on the set of "Rust" included managing firearms safely, was convicted of involuntary manslaughter in March for loading the live round.

Prosecutors will have to persuade jurors Baldwin is also guilty of willful and reckless criminal negligence.