A mistake often made by victims of violence by police officers is that of asking the potential defendant, the police department, for pictures and evidence. The problem with gathering evidence from a defendant is that any defendant in the United States has the right to put on a defense, and to refuse self incrimination, including the police. The best place to go in the event of police brutality is the nearest emergency room. Explain that you are a crime victim, and insist that the visit be handled that way. Even if you run into a physician who does not think you deserve medical attention because the police targeted you, he or she is obligated to treat you and document your visit. Of course, that cursery phone call to the sheriff that must be made by the hospital in the event of physical violence and abuse is often very awkward; how does one report the sheriff's department to the sheriff's department? The next step, of course, is keeping all paperwork from the emergency room for your lawyer's reading pleasure.
Marshall County Kansas tax dollars at work. Had the emergency room made the phone call attributing this to anyone besides a civil "servant" in law enforcement, probable cause for an arrest warrent would have been construed.