I had a similar situation several years ago...
I had finished doing a brake job for my 79 y/o neighbor.
We were gabbing in my driveway when bullets whizzed overhead missing us by mere feet. You guys may know what I mean, that whump, whump whump of a tumbling bullet.

He and I quickly headed to my back property where we found a Native American guy and his clan dragging a ivory-tipped bull elk down my back hill to the road.
They already had a large bull moose in the pickup bed.

I came back and called the local cops and they came out, only the Native cops could legally do anything. They showed up as well.
The guy admitted to after-hours hunting, but the dangerous silhouette/skyline shooting scenario was never addressed.
The guy was reprimanded by tribal police and as punishment instructed to kill more elk for the elders...true story.

Last I heard he was actually serving time for shooting a bald eagle.