Chicago isn't the only city with these problems. New York, Albuquerque and Baltimore have each doled out millions of dollars in recent years in cases that have sparked street protests and demands for reform.

In Chicago, though, the lack of police accountability, a code of silence and racial tensions tend to be more entrenched than in other cities, says Craig Futterman, a University of Chicago law professor and expert on police misconduct. "It's not that Chicago is overrun by bad or abusive police officers," he says, "... but here, a small percentage of officers has been allowed to abuse some of the most vulnerable Chicago residents with near impunity."

More than 80 percent of officers have fewer than four complaints for the bulk of their careers, he says, while a small number have accumulated more than 50 in five years and haven't been disciplined.

Futterman faults the Chicago police for not addressing patterns of abuse, noting that with some officers, "there was not just a trail of bread crumbs, but a trail of steak that if anyone would have bothered to look, it would have raised serious eyebrows."

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