Criminal charges are possible in the fatal shooting of Halyna Hutchins on a film set, a prosecutor has said.
Baldwin had been told the gun did not contain live ammunition before he started rehearsing with the weapon, authorities previously said.
Santa Fe County district attorney Mary Carmack-Altwies told the New York Times “we haven’t ruled out anything” in the investigation.
She added: “Everything at this point, including criminal charges, is on the table.”
Carmack-Altwies will be joined by Santa Fe County sheriff Adan Mendoza for a highly awaited press conference into the tragedy on Wednesday.
She said the investigation is focusing on what kind of round was in the gun that killed Hutchins – a 42-year-old rising star cinematographer whose death stunned Hollywood.
Who placed the ammunition in the weapon is another key question, Carmack-Altwies told the New York Times.
She said: “There were an enormous amount of bullets on this set and we need to find out what kinds they were.”
And it could be months before the investigation is complete, according to Carmack-Altwies.
She said: “It’s probably weeks, if not months, of follow-up investigation that we’re going to need to get to the point of charging.”
The prosecutor also took issue with reports the weapon was a “prop gun” as it has been named in court documents.
It was an “antique-era appropriate gun”, she said.
Hutchins was killed on Thursday in an incident which also left Rust director Joel Souza injured, though he is now recovering after leaving hospital.
Production on Rust has been paused while police investigate the incident.
According to court documents, an assistant director unwittingly handed Baldwin, 63, a loaded weapon and told him it was safe to use in the moments before the shooting.
Baldwin has since said he is heartbroken by the incident and is fully cooperating with the investigation.
According to Hollywood news outlet Deadline, Rust producers have opened an internal investigation into the fatal shooting.