I thought the same thing was happening to me this morning. The dogs we going nuts. I looked out and my garage door was open. (Wife forgot how the **** to use the remote to close it when she left for work?) In any event, I could see a truck in the ally and figured I better go investigate. I grabbed one of my assault shotguns and walked out there in my fricken robe. It turns out it was just some A-Clown grabbing some wooden pallets I had on the side of the garage. The poor bastard looks up and sees me standing there with a 12 gauge with a look I will never forget. He starts ranting on how he didn't think I would mind him taking the pallets. (Along with I think pissing himself) I told him if he would have come and asked, I wouldn't have had a problem with it, but told him I thought he had a big set of balls just taking them. I made him unload and restack the pallets before he left. ****ing douche bag.
As far as your guy, to bad you didn't have time to get to a gun with a little rock salt loaded up.