Can someone tell me if this is illegal?

Recently my mother was involved in a crash and it wasn't her fault. The other party involved was at fault but they where being followed by relatives or friends and they acted as witnesses saying that it was my mothers fault. I know they were relatives because after the accident my mother said they were calling each other by name. My mother had no insurance and I understand that it is very wrong to drive without proof of insurance but it was an emergency. They called the cops and the other party rushed to tell the officer whose fault it was. The cop was very racist to my mother of hispanic heritage and didn't even asked her for her side of the story. I arrived to the scene and i was just observing what was going on. The cop finished writing the report without asking my mother for anything besides telling her what her charges were. I read the report while this was going on diligently, and found out that the officer already proclaimed her (at fault). when the officer finished talking to my mom I asked him politely that under the law he should hear my mothers side of the story and he got very rude and told me that he was just about to do that (obviously not) and that I should step back. He took my mother somewhere else knowing that her English was weak and just rushed her to tell him what happened which was useless because he had already written the report and saying that she was at fault. I was very saddened by this situation because I felt that he was violating her rights. Can someone Please tell me what should I do? I have the report and police badge number. Need legal advice.