Every call to police dispatch (not the station, but the central dispatch number) is recorded on audio and a text record is typed up by the dispatcher. An "incident report" number will be assigned. The call is sent to a Deputy. If a deputy thinks there may be a crime he will likely create a Deputy Report which will get a number too: a DR#. One can request a deputy create a Deputy Report to make sure all the details are created. Most Deputies will request a DR# in the field over the radio and then hand a business card with the number on it to you.
One can obtain reports of incidents, deputy reports, and the audio wherein you made a complaint. If someone complained to the police about you and the case is closed, you may obtain such copies to see what they are saying about you. Even if the criminal investigation is ongoing, the Sheriff will tell you whether incident reports exist that name you as a suspect. They may also tell you the Penal Code section you are suspected of violating. In the middle of an active trial, one can subpoena the records of criminal complaints as well and your judge may allow you to see the information therein.
Both the sub-station in your area and the central Civil Liabilites department in San Bernardino can provide this reports to you. Unlike the sub-station personnel, Civil Liabilities is not dealing with emergencies so complex requests may be better asked of it instead of the local sub-station.
However, beware, Civil Liabilities can refuse to give you records and you can be forced to request a judge order them to deliver the records to the court.
Civil Liabilities will accept requests via email but the reports will be delivered by mail or may be picked up at the window.