To Do If Your Rights Are Violated at a Demonstration or Protest | American Civil Liberties Union

https://www.aclu.org/know-your-rights/what-do-if-your-rights-are-violated-demonstration-or-protest

The right to join with fellow citizens in protest or peaceful assembly is critical to a functioning democracy. But it is also unfortunately true that governments and police can violate this right – through the use of mass arrests, illegal use of force, criminalization of protest, and other means intended to thwart free public expression.