There probably have ALWAYS been bad cops, I remember the Arthur McDuffie case in Miami in 1980, many bad cops before that, WHO NEVER SHOULD HAVE BEEN HIRED IN THE FIRST PLACE.
Drive by shootings were extremely rare prior to the 1980's, black neighborhoods were FAR LOWER in crime before the 1980's, ( I know in the 1960's Patrick Moynihan said Blacks born out of wedlock had reached crises levels (Slightly over 20%) now it is over 70% not that that has anything to do with crime but it shows a turn for the worse) everything has regressed since the Gangster/negative rappers started glorifying crime.
Rappers should rap teach about the negative effects of crime and how to make things better, In a study of black cab drivers in Washington D.C. they said they often pass up picking up black customers do to the stats showing they are more likely to rob them, in many (not all) black neighborhoods bars are put over windows, because they are worried about someone breaking in (Which happens in every neighborhood, but far more in black neighborhoods) no one put bars on windows before rappers started glorifying crime.
Crime has DEFINITELY RISEN since rappers started glorifying crime, before the 1980's (When Rap became big) recreation centers were not named after career heroine dealers, ask any cop why so many black murders go unsolved, they will tell you because of the no snitch code (The no snitch code was started by a rapper and it has gone wide spread) blacks like all people used to tell what they knew to cops, now they often won't tell/snitch even if the victim is a infant (Meaning incapable of doing anything to instigate or provoke their attacker)