A New Mexico judge has upheld her decision to dismiss an involuntary manslaughter charge against Alec Baldwin in the fatal shooting of a cinematographer on the set of a Western movie.

In a ruling Thursday, District Court Judge Mary Marlowe Sommer stood by her July decision to dismiss an involuntary manslaughter charge against Baldwin. She said prosecutors did not raise any factual or legal arguments that would justify reversing her decision.

"Because the state's amended motion raises arguments previously made, and arguments that the state elected not to raise earlier, the court does not find the amended motion well taken," the judge wrote, adding that the request was also untimely.

A spokesperson for Baldwin's lawyers said Friday that they had no immediate reaction to the decision.

Special prosecutor Kari Morrissey told The Associated Press that she disagrees with the court's analysis and will appeal the ruling. Morrissey was appointed by the Santa Fe district attorney to take over the case in March 2023 after a previous special prosecutor resigned following missteps in the filing of initial charges.

Allegations of withheld evidence

The case was thrown out halfway through trial on allegations that police and prosecutors withheld evidence from the defence in the 2021 death of cinematographer Halyna Hutchins on the set of the film Rust.

Baldwin's trial was upended by revelations that ammunition was brought into the Santa Fe County sheriff's office in March by a man who said it could be related to Hutchins's killing. Prosecutors said they deemed the ammo unrelated and unimportant, while Baldwin's lawyers say investigators "buried" the evidence in a separate case file and filed a successful motion to dismiss.

WATCH | Judge dismisses charges against Alec Baldwin:

Judge dismisses charges against Alec Baldwin

A New Mexico judge dismissed involuntary manslaughter charges against actor Alec Baldwin on Friday after his lawyers alleged police hid evidence of the source of the live round that killed Rust cinematographer Halyna Hutchins in 2021.

Baldwin, the lead actor and co-producer for Rust, was pointing a gun at Hutchins during a rehearsal on a movie set outside Santa Fe in October 2021 when the revolver went off, killing her and wounding director Joel Souza. Baldwin has said he pulled back the hammer — but not the trigger — and the revolver fired.

A judge in April sentenced movie weapons supervisor Hannah Gutierrez-Reed to the maximum of 1.5 years at a state penitentiary on an involuntary manslaughter conviction in Hutchins's death.

Marlowe Sommer last month rejected Gutierrez-Reed's request to dismiss her conviction or convene a new trial on allegations that prosecutors failed to share evidence that might have been exculpatory. She found that the armourer's attorneys didn't establish that there was a reasonable possibility that the outcome of the trial would have been different had the evidence been available to Gutierrez-Reed, who still has an appeal pending with a higher court.