Sorry for your misfortune. Good thing you were only bruised.
Helmet cam for the win. New bike and more with even a 1/2 arse attorney. Could have been much worse and that is the monetary point to be made. Just no excuse for it.
Depending on the situation that can be much easier said than done.
If that was a typical small-town police department, they won't have much money available so it will take a long time to collect, if you ever actually do. Also, if you live in a small community even if you are one hundred percent in the right suing the local police isn't going to make you popular.