IyaMan
Addicted to ArboristSite
If you have a business you probably already have an attorney that you use, maybe pop in for a quick chat to see whats legal and whats not as far as surveillance, preventative measures, what will carry weight in court, etc.
Yeah, knowing whats legal or not in your town/state will prevent further headache (though if its just your property in the video it should be no problem). Lots of advice here is coming from all over the place, but laws can be pretty specific according to the area.
And also be careful what you do and who you show the video to if you do catch them. You don't what to wreck your evidence by posting it on Facebook.