sure there are some bad apples.Not sure. A lot more than 38 though. And it's not just shootings. It's organized criminal activity by Police, planting drugs, rape, police brutality, etc. It happens on a daily basis. Look at the 815 Harding St. raid in Houston. These guys had a system in place and would have gotten away with it - if the cops coming in the house from opposite sides hadn't shot each other.
Just peruse this forum which keeps track of many of the abuses by the police. https://www.reddit.com/r/Bad_Cop_No_Donut/
Having police is a great idea in concept - but we can no longer trust them (as with any government agency - they aren't working in our best interests despite what they say).
But a pretty dang small amount if you look at it on a percentage basis.