Police not in court, what is going on?

I have been very out of touch with a lot of the news going on on the mainland.  I've been catching up and I have to wonder what decade the rest of the country is in.  If someone attacks another person on the street, doesn't do anything when they are obviously not all right (doesn't call for medical attention, etc.), and the person then dies---there is going to be some time in court, someone is probably going to jail, at least temporarily, and the matter will be thoroughly investigated ... right? ... apparently unless you are a police officer.  Then nothing really happens and it is ignored by the courts.  Do I really have to say this is crazy?  Shouldn't police be held to the same standard as normal people?  In fact, shouldn't they be held to a higher standard?  They are supposed to be trained to protect people, and are trained in and entrusted with lethal force; it's not a time to lower your standards and look the other way---I feel silly even saying this because it should be obvious, but apparently it isn't.  The job of the courts is to make decisions and satisfy people so they don't take the law into their own hands and carry out revenge and vigilante justice.  By ignoring these events the judicial system is playing a very dangerous game.