In any case where criminal charges are filed for involuntary manslaughter, the focus for the prosecution is on culpable negligence or due caution/care. 

The facts and testimony of the people who were on the set, as well as the firearms' expert(s) will be critical.

Alec Baldwin will be charged with involuntary manslaughter for handling the gun that discharged on the set of “Rust,” killing its cinematographer, as will the movie’s armorer, who loaded the gun, prosecutors in New Mexico announced on Thursday.

www.nytimes.com/...