Good idea about authorizing neighbor to fish & keep watch, RAH. I'm gonna try to do exactly that.
Things are looking up a bit, as the miscreants were spotted trying to trespass again. Neighbors saw them, called them out, got pics of them & the car that dropped them off. Unfortunately from a legal standpoint, they were stopped before getting on my land, but neighbors know who they are.
Maybe there is some hope, we'll see. I've been told they released fish, which is better than killing them, but then again who knows?
It all depends on how the fish were handled too. They could have released them just to have them die a few days later. I hope you get to the bottom of this, and soon.