The camera is by far the best Idea, You can't injure people with traps but you can use wet paint. Black or brown paint or roofing tar at the entrance is sure to make a real mess, especially if the culprit make a get away in a car.
We had people stealing items from our vehicles, the last thing they stole was 5Lbs. of honey bee's "accidentally" left in a old tool box over night.