Can you solve the crime on your own without making yourself the jury and the executioner? I know, it'd be tough not to just beat the crap out of the guy, but here's what I'd think, if you're really serious about fixing the problem.

First priority, keep yourself safe. By that, I don't mean carry a weapon with the hopes you're faster than him (not necessarily a bad idea, but that's a last resort, not Plan A), but rather keep yourself out of site. Whether this is a hard-core crime ring or (more likely) some local punk needing meth money, it's better if he doesn't see you.

Given that, just set a bait car, and some kind of surveillance. If you can use several cameras from different angles, you could just go to bed at night and wait for him to hit, then review the tapes.

Another plan would be to stake it out, sit somewhere and wait and watch, then take pictures. Again, if you can keep yourself safe, you could even follow him home.

The more evidence you can give the cops, the better. So if you have videotapes, and his license plate, and his address, and you do a little extra poking around and can even give his name, all the better.

On the other hand, you can always pick him out of a photo lineup - "Yes, sir, I'm sure that's him. I recognize the cracked skull."

I'm not a detective, but I did stay at a Holiday Inn Express last night.