Mystery remains: Why were live rounds on Alec Baldwin movie set where shooting occurred?

During a news conference Wednesday, Santa Fe County Sheriff Adan Mendoza said there was "some complacency" in how weapons were handled on the set.

Light from a high afternoon sun slanted through the tall windows of the weathered wooden church, catching on the plank floorboards and illuminating the stained glass. Outside, the arid ground of the northern New Mexico foothills stretched for miles — a picturesque setting for an Old West gun battle.

The actor Alec Baldwin, haggard in a white beard and period garb as he played a wounded character named Harlan Rust, sat in a pew, working out how he would draw a long-barreled Colt .45 revolver across his body and aim it toward the movie camera.

A crew readied the shot after adjusting the camera angle to account for the shadows. The camera wasn’t rolling yet, but director Joel Souza peered over the shoulder of cinematographer Halyna Hutchins to see what it saw.

Souza heard what sounded like a whip followed by a loud pop, he would later tell investigators.

Suddenly Hutchins was complaining about her stomach, grabbing her midsection and stumbling backward, saying she couldn’t feel her legs. Souza saw that she was bloodied, and that he was bleeding too: The lead from Baldwin’s gun had pierced Hutchins and embedded in his shoulder.

A medic began trying to save Hutchins as people streamed out of the building and called 911. Lighting specialist Serge Svetnoy said he held her as she was dying, her blood on his hands. Responders flew Hutchins in a helicopter to a hospital, to no avail.

A week after the Oct. 21 shooting on the set of the movie “Rust,” accounts and images released in court documents, interviews and social media postings have portrayed much of what happened during the tragedy, but they have yet to answer the key question: how live ammunition wound up in a real gun being used as a movie prop, despite precautions that should have prevented it.

During a news conference Wednesday, Santa Fe County Sheriff Adan Mendoza said there was “some complacency” in how weapons were handled on the set. Investigators found 500 rounds of ammunition — a mix of blanks, dummy rounds and what appeared to be live rounds, even though the set’s firearms specialist, armorer Hannah Gutierrez Reed, said there should never have been real ammo present.