Alec Baldwin thought he had a safe prop gun in his hands when it went off, killing one person and injuring the director.
That's according to an affidavit filed in court, which offers the best look yet at the disastrous shooting on the set of a Western called Rust last Thursday.
It all sounds like a horrible mishap involving a loaded gun, a single shot and a breakdown in communication on set.
Cinematographer Halyna Hutchins and director Joel Souza were lining up the camera at the time of the shooting, while Baldwin was pretending to draw his gun and point it at the lens.
The gun went off as Baldwin was rehearsing with it, hitting both Hutchins and Souza, according to the affidavit obtained by the New York Times.
Souza heard a "whip and then loud pop," then he realized he was bleeding from the shoulder.
Hutchins stumbled back from the camera a moment later and Souza saw that she was bleeding from the midsection.
Both of them were taken to hospital where Hutchins, 42, ultimately died.
Investigators are now focusing on the movie's armorer and assistant director, who were both apparently supposed to check the guns before they ended up in the actors' hands.
Souza told police that the assistant director, Dave Halls, shouted "Cold gun!" before he gave the prop to Baldwin. That's code for a safe gun.
Police are also trying to learn exactly what happened with that gun, which was apparently left out on a cart with two other guns while everyone broke for lunch.
Detectives say Halls grabbed one of the guns after lunch and gave it to Baldwin without knowing that it had a live round in it.
The affidavit also describes some earlier issues on the set, including other cases of prop guns going off and labour issues with the crew.
No one has been charged at this point and Baldwin has described it as a "tragic accident."
Production on the movie has been halted.