On March 20 in the St. Louis County town of Florissant, someone made an illegal U-turn in front of Nicole Bolden. The 32-year-old black single mother hit her brakes but couldn’t avoid a collision. Bolden wasn’t at fault for the accident and wanted to continue on her way. The other motorist insisted on calling the police, as per the law. When the officer showed up, Bolden filled with dread.