Police Brutality

My research topic hasn't change at all but the question changed just a little to have a clear focus and thought about. Why are police acting up to the point where they injured and kill innocent lives on accident or purposefully? This is my question but I might still work on it to make more sense in the way its good enough, clear and understandable. On the essay portion, I'm thinking of starting off by saying a little history or incidents that had happened in the past few years to get it going then as I get to middle of the essay, explain maybe why police officers may do this and think they can get away. Also, why I'm still in the middle portion of the essay have some positive and negative effects of the action that took place and still have today. Afterwards ill probably end it with some facts and results of the crisis that was left or something else. Not to sure for sure since it is a working progress still and I am researching still to get more information. I do feel like it will be a good topic for me because law enforcement is my major that I'm going for and I feel like its something that I can write about and learn a few things about along the way. If you have any suggestions as to how I should go about on the essay feel free to ask or tell. It would be helpful to know since I'm not the best at writing but do have some ideas as how to do it. I want to make this essay readable and understanding for those who don't know what is happening out there in the world or want a little more insight on what is actually happening in the police force.