STORY: "The sanction of dismissal is the only warranted remedy."

Actor Alec Baldwin's involuntary manslaughter trial in the "Rust" set shooting case ended Friday - and he walked free.

A New Mexico judge dismissed charges on Friday, agreeing with Baldwin's lawyers that prosecutors and police withheld evidence on the source of the live round that killed cinematographer Halyna Hutchins in 2021.

Prosecutors allege Baldwin played a role in the death of Hutchins because he handled the gun - a Colt.45 revolver - irresponsibly.

But several developments upended their case.

The actor's lawyers alleged the prosecution received ammunition in March, which resembled live rounds that were fired on set, but the prosecution failed to list them in the "Rust" investigation file, or turn them over to the defense team.

Under questioning by the judge a corporal from the sheriff's office said lead state prosecutor Kari Morrisey took part in the decision to put the ammunition into a separate case file number.

Judge Mary Marlowe Sommer blasted the state's handling of the evidence.

"The case agent, as well as pursuant to Hancock's testimony, Ms Morrisey, was aware of the new evidence and yet did not make an effort to disclose it to defense. The state's willful withholding of this information was intentional and deliberate. If this conduct does not rise to the level of bad faith, it certainly comes so near to bad faith as to show signs of scorching."

Baldwin left court without speaking to reporters. His case has been dismissed with prejudice - meaning it can't be brought against him again.

It ends an unprecedented criminal prosecution against an actor for an on-set shooting.

Missteps hounded prosecutors since first filing charges 18 months ago, and four prosecutors have quit or were forced to step down - the latest being Erlinda Johnson, who resigned Friday.

A legal expert and former prosecutor in New Mexico, John Day, called the state's efforts a "disaster":

"It was a stunning conclusion to this Alec Baldwin prosecution. It was a disaster for the special prosecutors, it raises questions about this entire investigation. You had a judge who was obviously ticked off at all the missteps in the prosecution and she finally said the only response, the only logical answer is to dismiss this. No, this was really.... It was like watching the Titanic go down, sadly."

It's unclear whether the dismissal of his case would affect the conviction of "Rust" armorer Hannah Gutierrez, which is under appeal.

Baldwin's lawyers in the trial had alleged prop supplier Seth Kenney supplied the live rounds to "Rust," an accusation he denied in testimony. Kenney has not been charged in Baldwin's case.