This is so simplistic that it borders on a racist falsehood. Increased police presence, inadequate legal representation, racially motivated jury-selection and expansions of prosecutorial power are huge factors.
Educate yourself.
Poverty tends to beget crime, this is very hard to deny. Because the black community - as a result of the slavery of its ancestors in this country - suffers disproportionately high rates of poverty, it also suffers from disproportionately high rates of crime.
> "Educate yourself."
The topic at hand is highly contentious. Regardless of how wrong you think the other party may be, it behooves us to strive to be even more civil in our discourse in such circumstances.