Alec Baldwin shooting press conference by police

Investigators probing the fatal movie set shooting by Alec Baldwin said Wednesday that they believe they have found the lead projectile that caused the death of cinematographer Halyna Hutchins.

Authorities said the object was recovered from the shoulder of director Joel Souza, who was injured during the incident on the New Mexico set of the Western film “Rust” Thursday.

The investigation has also turned up the gun and spent casing that is believed to have been used in the accidental shooting, said Santa Fe County Sheriff Adan Mendoza during a joint press conference Wednesday with the First Judicial District Attorney Mary Carmack-Altwies.

Mendoza said 500 rounds were located on set, which were a mix of blank ammunition, dummy rounds and, possibly, live rounds. Mendoza declined to comment on how live rounds may have gotten on set. Evidence collected will be submitted to the Federal Bureau of Investigation crime lab in Quantico, Virginia for analysis, he said.

Other items collected from the set included clothing, accessories and three firearms. One is a long Colt revolver, which authorities believe is what was used in the shooting. The others were a single-action revolver that may have been modified and a plastic prop gun that was described as a revolver.

Mendoza said investigators are still collecting evidence and are not yet ready to determine if charges should be brought in the case.

“We are not at that juncture yet,” said Carmack-Altwies about the possibility of bringing charges against any members “Rust” crew. However, criminal charges are not off the table, she told The New York Times Tuesday.

“If the facts in evidence and law support charges, then I will initiate prosecution at that time. I’m a prosecutor that was elected in part because I do not make rash decisions and I do not rush to judgment,” she said.

Mendoza said that while film industry has a history of following safety procedures when it comes to on-set firearms and prop weapons, there seems to have been “complacency” on the set of “Rust.”

“The people that inspected or handled the firearm when it was loaded before it got to Mr. Baldwin — we’re interviewing. And there [are] some follow-up questions that we need to do,” Mendoza said.

Representatives for Baldwin and Souza declined to comment to NBC News.

This update comes just a day after the producers of “Rust” hired a high-profile law firm to interview cast and crew about the accidental on-set shooting.

Court documents released Friday show Baldwin was handed a loaded weapon by assistant director Dave Halls. Halls had retrieved the gun from a cart, where it had been placed by the armorer, Hannah Gutierrez Reed. Halls indicated it was safe to use moments before Baldwin…