I have a small mig welder in my garage and I built my own camera security box from scrap steel that I had laying around in some boxes. I always carried home scraps from my last job building rock crushers because you never know when they will come in handy. I only wish I had saved more now.
I built it so the front was open and didn't interfere with the picture taking or the flash, but it's impossible to remove the camera from it. Then I welded two very large nuts, one on each side to run a cable lock through after it was strapped to the tree. It would be impossible for anyone just wandering through to remove the camera or the lock box without cutting the entire tree down. I guess if they want it bad enough, they will come back for it? But it will keep an honest man honest, but nothing will stop a thief if they are dead set on stealing from you.
I hope you catch whoever did this and give them a thumping, or have them arrested.
Sorry for your loss, I know how bad it sucks and these days you just can't trust anybody anymore.
I've even had traps stolen in the dead of winter around the river here where I live. So I know for a fact that it was another trapper who stole them, and not just somebody passing through. That is really bad when one of your fellow trappers would steal from you, I guess I was wrong to assume that we were all a "Brotherhood" and had a certain degree of respect and honor for each other. Honor, Integrity, and Respect are three virtues that the world is short on these days.......don't wrongly assume that everybody has the same values that you do.