Prosecutors in New Mexico have downgraded the involuntary manslaughter charges against actor Alec Baldwin in the fatal shooting of cinematographer Halyna Hutchins on the Rust movie set in October 2021.

Court documents filed on Friday show that Baldwin still faces one count of involuntary manslaughter, a fourth-degree felony that carries a sentence of 18 months in prison.

But prosecutors have removed what's known as a firearm enhancement, a part of the criminal code that extends prison sentences when firearms are involved in the commission of a crime.

The decision comes more than a week after the actor's legal team disputed the enhancement charge in filings, arguing that the prosecutors had committed "an unconstitutional and legal error by charging Mr. Baldwin under a statute that did not exist under the state of the accident."

Changes to New Mexico's firearm enhancement law took effect in March 2022. The current version of the law calls for five additional years of prison time in cases in which a firearm was "discharged" in the commission of certain felonies.

But Baldwin's lawyers had pointed out that the Rust shooting took place in 2021, about six months before the changes took effect. Under the previous version of the law, an enhancement of three years would only apply when a gun had been "brandished," which would have required prosecutors to prove an intent to intimidate or injure.

In a statement to NPR on Monday, Heather Brewer, a spokeswoman for the New Mexico First District Attorney, said the decision to drop the firearm enhancement was made to expedite the case.

"In order to avoid further litigious distractions by Mr. Baldwin and his attorneys, the District Attorney and the special prosecutor have removed the firearm enhancement to the involuntary manslaughter charges in the death of Halyna Hutchins on the 'Rust' film set," Brewer said.

She added: "The prosecution's priority is securing justice, not securing billable hours for big-city attorneys."

The same charges have also been dropped against the film's armorer, Hannah Gutierrez-Reed, who faces the same involuntary manslaughter charge as Baldwin.

Baldwin is expected to make his first court appearance on Friday.