Somebody reported me as a hit and run. What to do?

Asked by Amazebyu (488) October 8th, 2010 from iPhone

Last august I was driving on the freeway in LA. It was bumper to bumper the traffic wasn’t moving much and when it barely started moving the car in front of me braked and so did I but I did hit his bumper. Although nothing happen to the other car (an late 90s corolla) I did pull over to check my car fender. The other car kept driving, he didn’t seem to have any intention to stop. So since nothing happen to my car either. I decided to get back on the road. Apparently somebody saw me taking off and called the highway and report a hit and run. Now I got a paper over the mail and I have to call and explain the exact same thing. Also, according to the letter I received there was no report from the car I hit. Only the person who saw me leaving after pulling over. Any ideas what’s to expect?