* Training Day (2001): This is probably the most well-known example. Denzel plays Alonzo Harris, a corrupt narcotics officer who mentors a rookie cop (Ethan Hawke) while pushing him into the world of crime. Alonzo's actions are undeniably bad, but the film explores the complexities of his morality and the pressures of the system he operates within.
* American Gangster (2007): Although not technically a cop, Denzel's character, Frank Lucas, is a crime lord who operates with a certain "code" and respect for authority. He works closely with corrupt police officers, blurring the lines between good and bad.
* The Equalizer (2014) and The Equalizer 2 (2018): Robert McCall, the character Denzel plays, is a former government agent who uses his skills for good. However, he operates outside the law and sometimes uses brutal methods to achieve his goals, which could be considered "bad cop" territory.
While these are just a few examples, it's important to consider the context of each film and the complexities of each character. Denzel Washington is known for his nuanced performances, and even his "bad cop" roles often explore ethical dilemmas and the gray areas of morality.