PIT maneuver in some states is also deadly force. Why go to IA? That would be like a passenger going to ALPA to complain about a pilot.
If you can not handle the pressure of being a Cop, then you shouldn't be one. It is your job to set the example.
Bring civil charges, then small claims.
It may seem like I am anti-police, which I am not, but I DO believe that the position of is one which ABSOLUTELY can not, and must not tolerate anything except perfection. When you put the badge on, you have given your life to protect the public. You HAVE NOT gained the right to indiscriminately use force against those you are sworn to protect in your own interests. Our Military can not shoot without positive identification, and often until they are fired upon, but apparently, our Police force may fire upon those they protect if they feel it is warranted.
I see a serious lack of judgment again by the officer. A lapse like that in my job, would cost me my career i am sure. Assaulting a passenger who was going to the lav when I said no, would get me fired... I feel similar should happen.