“Its police department has 52 sworn officers. Only three are black, when about 68% of the city’s population is black.”
I would imagine that the officers are required to be able to read.
From the article:
In Missouri, 56% of black men graduate from high school, where 81% of white men do (National Table Data). 27% of white Americans have poor credit records, where 48% of blacks do (Study: African-Americans More Likely to Have Bad Credit | BadCredit.org). The reasons for this are an entirely separate debate, but it boils down to there being substantially fewer black men than white men who are qualified to be police officers.