Battery Charge in California

My question involves criminal law for the state of: California.

I received a letter from an investigator at the Police dept stating to call him. I called him a few days ago, but he hasnt called me back. I know its from a battery charge where I hit somebody in the face one time before we were detained.
At the incident, the cops arrived and took a report. I do not believe I seriously injured the guy, because i was not arrested and the guy didnt press charges (at the time).
The investigator has not called me back, but i am wondering what will be the result of these charges?
I have no prior history.

If you're charged, you'll be prosecuted for whatever crime it is that you're charged with committing.

The police are primarily interested in getting you to make self-incriminating statements. If you continue to communicate with the officer it's much less likely that you'll talk your way out of charges than it is that you'll make statements that help the police and prosecutor prove a case against you.