Many articles and discussions on police criminal activity carry a tone of surprise, but in my view nothing here is surprising considering that large numbers of questionable individuals who passed some subjective selection process are armed with guns and placed into what are essentially life-long appointments where lots of money and power is at stake. In my mind it would be surprising had there been no criminal activity within the police under the current system. It would be just as surprising if dictators stayed benevolent and never abused their authority.
I'd say the solution to this problem is to have the public democratically elect police just like politicians, and to also have them be subjected to term limits just like politicians.
So far this system has successfully prevented most people who should not be politicians from becoming politicians or maintaining political power, and I argue that in the same way it would prevent lots of people who should not be in the police from becoming or remaining police officers.