Cop 1: This murder seems racially motivated...
Cop 1: This murder seems racially motivated.
Cop 2: Hate crime?
Cop 1: Of course I hate crime. That’s why I’m a cop.
This joke is a misunderstanding - Cop 2 asked "[do you think it was a] hate crime?", and Cop 1 heard "[Do you] hate crime?" that misunderstanding is the source of the humor in this joke.