Investigators spent more than a year sorting out blame for the death of Halyna Hutchins, the cinematographer killed on the set of “Rust.” In the end, two agencies came to two sharply different conclusions about Alec Baldwin’s level of responsibility as a producer of the film.

Prosecutors charged Baldwin for firing the gun that killed Hutchins, but also for management failures that created a hazardous set.

“We believe Baldwin, as a producer, knows everything that goes on, on the set,” prosecutor Andrea Reeb said on Fox News’ “The Five” last month. “There were a lot of safety concerns that were brought to the attention of management, and he did nothing about it.”

But in a parallel proceeding, the New Mexico division of the Occupational Safety and Health Administration found that Baldwin was not in charge and was not the one culpable for lax oversight.

“He didn’t actually have...