Assistant director handed the loaded gun to Alec Baldwin

An assistant director handed the gun to Alec and told the actor it was safe to use before the deadly incident, according to the warrants.

The warrant says the gun on the "Rust" movie set was loaded with a live round.

The assistant director didn't know the gun was loaded, but it doesn't mention who actually loaded the gun ... which may become the central issue.

Alec's blood-stained costume from the movie has been taken as evidence, as well as the gun that went off, plus other prop guns and ammo being used on set, according to the warrant.

Alec pulled the trigger on the gun and the accident resulted in the death of 42-year-old cinematographer Hutchins. She was struck and airlifted to a hospital, where she died. Director Souza was also hit, but has reportedly been released from the hospital.