Sucks that you can't prove who did it. People can be such totally spineless a-holes.
I was following some guy in a F-150 one day down a residential street. We passed by some parked cars but he didn't judge the distance very well and ended up tasking off one of the parked vehicle's outside mirrors. He kept on going like nothing happened, so I kept following him until we got to a main highway. He turned abruptly into an alley running parallel to the main highway and I stayed with him; he obviously realized that I was following him. He turned into a parking lot and I pulled up behind him, got his plate number, and got out of there in case he decided to come after me and do something (road rage). I went back to the house where the collision occurred. The owner was there looking at his car and he recognized my car, so I parked and gave him the plate number, make model, and a good description of the driver.
Too bad back then there were no cell phone cameras (this was probably a good 12 years ago).