Unlike the local investigators, the Justice Department did not merely toss all evidence before a grand jury and say, "you figure it out." The federal investigators did the work themselves and came to the conclusion that Officer Wilson had not committed "prosecutable violations under the applicable federal criminal civil rights statute, 18 U.S.C. § 242."
Our system, ideally, neither catches every single offender, nor lightly imposes the prosecution, jailing, and fining of its citizens. A high burden of proof should attend any attempt to strip away one's liberties. The Justice Department investigation reflects a department attempting to live up to those ideals and giving Officer Wilson the due process that he, and anyone else falling under our legal system, deserves.
One cannot say the same for Officer Wilson's employers.
The Justice Department conducted two investigations—one looking into the shooting of Michael Brown, and another into the Ferguson Police Department. The first report made clear that there was no prosecutable case against one individual officer. The second report made clear that there was a damning case to be made against the system in which that officer operated:
Ferguson’s law enforcement practices are shaped by the City’s focus on revenue rather than by public safety needs. This emphasis on revenue has compromised the institutional character of Ferguson’s police department, contributing to a pattern of unconstitutional policing, and has also shaped its municipal court, leading to procedures that raise due process concerns and inflict unnecessary harm on members of the Ferguson community. Further, Ferguson’s police and municipal court practices both reflect and exacerbate existing racial bias, including racial stereotypes. Ferguson’s own data establish clear racial disparities that adversely impact African Americans. The evidence shows that discriminatory intent is part of the reason for these disparities...
Partly as a consequence of City and FPD priorities, many officers appear to see some residents, especially those who live in Ferguson’s predominantly African-American neighborhoods, less as constituents to be protected than as potential offenders and sources of revenue...
The "focus on revenue" was almost wholly a focus on black people as revenue. Black people in Ferguson were twice as likely to be searched during a stop, twice as likely to receive a citation when stopped, and twice as likely to be arrested during the stop, and yet were 26 percent less likely to be found with contraband. Black people were more likely to see a single incident turn into multiple citations. The disparity in outcomes remained "even after regression analysis is used to control for non-race-based variables."
One should understand that the Justice Department did not simply find indirect evidence of unintentionally racist practices which harm black people, but "discriminatory intent”—that is to say willful racism aimed to generate cash. Justice in Ferguson is not a matter of "racism without racists," but racism with racists so secure, so proud, so brazen that they used their government emails to flaunt it.