These stories of police corruption come from north and south, from many different cities and neighborhoods.
This isn't police corruption, it's police brutality, which is a separate issue. I have friends and family members who are police officers, the lion's share of them are decent people, but knowing them and the small handful of their colleagues who aren't decent people I can proffer a few opinions on what drives behaviors such as these:
Isn't brutality a form of corruption? brutality is simply to shape rules in a way they see fit, with no regards for consequences. Ok, there's no profit, but brutality is a form of corruption anyway.