Choose a case in the United States in which protests and/or political unrest led to arrests and was catalogued as police malpractice. Explain the case in 2

Choose a case in the United States in which protests and/or political unrest led to arrests and was catalogued as police malpractice.
Explain the case in 200 words, and explain how did the authorities handle the case. (If any of the police officers was arrested, if they're convicted already, etc.)