Geezus. That looked like something out of a very old western. If I may give a bit of unsolicited advice, I'd learn more about the guy if I were you. I myself don't respond much to threats but think most of the time about my family. It's bad to let it pass, but if pursuing it puts anyone else in danger I think discretion should be your byword.

By all means post his plates here, I'll see if I can get him on a watchlist of sorts for checkpoints.