If you aren't involved with the local Humane Society and the county has one- I would start there. Then, look into local government -research who they are online, and even attend a meeting if you can (commissioners' meetings, city council). The state legal codes help determine who is responsible for which laws. I am in Ohio and the ORC, Ohio Revised Code, is what we follow - you can look it up and search "dogs", and "animal neglect", etc to see who you need to work with. Attend board meetings for your local shelter and ask the board how to advocate for animals in need and the shelter if their mission supports abuse and neglect cases.
It may also help to advocate for the animals involved in the cases to raise awareness and gain support.
Good luck and thanks for wanting to help animals in need. Unfortunately, there are a lot of them and it seems to be getting worse lately.