I can relate to having a pest in the garden and trying to figure out what it is. I recently had that problem too. The trail cam is a good idea if you have one,. I didn't. . I thought i had possum, in my garden it was rooting like a hog for worms. I tried cat food and then fresh fish. Nothing. then finally caught a possum.
If you live where there are ground hogs or rabbits. you might try peanut butter or carrot.as bait. Deer would probably leave tracks
I had deer problems,.they seemed to like beans and potatoes best. I bought an electric fence and tied cloth with peanut butter on it to the wire.so they touched the fence with their nose.and have never had another deer problem.