Legal Advice for Car Accident?

[KingCondanomation]

I was parked out in front of a mall and when I came back I find a note attached to my car which says that they witnessed a pickup truck back into my car and make a big crack in the bumper and they left the license plate of the truck that supposedly did it and the time it happened.
And sure enough there is a big crack in the bumper.
They did not leave their name or any contact info, so I don't know who this witness is.

So now what? Do I have enough with just this note to go after the truck that supposedly did this and get them to pay? Should I go through the cops or is there some way of tracking down plates myself and see if the guy just might pay without legal recourse?
I was thinking of contacting insurance but I don't want my rates to rise over a crack in plastic that although I wouldn't mind it fixed, if it came down to me paying I would rather just live with it.
Would the insurance company accept that note as proof I wasn't the one who actually made the crack?

 

[DamnYankee]

Call a cop. The owner of the truck broke the law and left the scene of an accident. With his plate number and his paint on your car they should have no problem proving the case.