SANTA FE, N.M. (AP) — Alec Baldwin fatally shot a cinematographer on a New Mexico film set with a gun a crew member had assured the actor was safe, a tragic mistake that came hours after some workers walked off the job to protest conditions and production issues.

An assistant director, Dave Halls, grabbed a prop gun off a cart at a desert movie ranch and handed it to Baldwin during a Thursday rehearsal for the Western film "Rust," according to court records made public Friday.

"Cold gun," Halls yelled, declaring the weapon didn't carry live rounds and was ready to fire.

But it wasn't. When Bal...