Research this case.
White police officer who shot unarmed black man to death found guilty of manslaughter in Virginia - LA Times
There's a film about it called "Unarmed Black Man" it exposes a lot about the cop and that he had already killed a man and about his love of guns. He should never have been allowed to carry a gun, let alone be a cop.
The solution is to sue the police departments so much they can't afford to ignore the signs and allow unsuitable people into the police force.