So Officer Wilson did nothing wrong, but the DOJ is going to make Ferguson pay. Or at least consent. To a Decree, that is.
The federal government has unlimited assets (it thinks, and they are your assets, btw). Cities don't. So when the DOJ comes to town and demands you comply with their demands, city after city recognizes that they have no alternative but to capitulate. The case of Portland, Oregon, is more unusual as that city asked to be put under a Consent Decree with the DOJ, but in the vast majority of cases the DOJ comes with a stack of filings as high as the dollars the city can cobble together. And DOJ knows that federal judges are more often than not willing to let DOJ run roughshod over mere municipalities. So what's the downside from DOJ's perspective? Why not threaten suit after suit after suit until you get your way?
Mafia Dons are envious of this kind of "weight".
So since nothing regarding the case of Michael Brown can be discovered which would rise to an actionable level the DOJ, instead, wants to go after the Ferguson PD over what DOJ claims are racially discriminatory policies. There don't have to be any actual discriminatory policies. There just has to be an imbalance of resources between petitioner (DOJ) and respondent (Ferguson, in this case) which makes fighting federal totalitarianism too costly and difficult to entertain.
I hope that in the case of Ferguson that the city at least gives the purported DOJ claims careful scrutiny before agreeing to encumber their citizens--ironically a large portion of which are black and will have to pay so that DOJ can claim to be "on the job"--with higher costs (or lower benefits elsewhere). And if that scrutiny reveals DOJ, as in other cases, is only after said municipality because it can go after said municipality, then fight the issue.
If you agree to the Decree then all claims of racism will be asserted as true. This despite there being no evidence to make such claims. This is how DOJ does business today. And it's not good for America.