COMMENT POSTED TO AN ARTICLE IN SPUTNIK
I don't doubt there are cases of this.
However, I think stupidity and poor psychological make-up are the main things responsible.
America has countless police forces for all its little towns and villages and cities.
They do not have the resources to run proper policing.
Candidates are not tested as they should be.
Also, all new police should be on probation for at least a year to see whether their behavior is suitable.
But these things require resources often not available in America's urban sprawl towns and underfunded cities.