One is a business owner whose surveillance footage captured the incident. The other helped the first cellphone video of Sterling's death go viral.
Footage from the incident in Harlem shows the officer pointing his weapon at a bystander while he and another officer pin a suspect to the ground.
With public confidence in US law enforcement at a 22-year low, people all over the country are teaming up to patrol their streets and train cameras on police to make sure they obey the law too.
Moore was himself arrested by police on Thursday, and released Friday without charge. He said that police had already interviewed him for several hours about Gray's arrest before he was taken into custody.
Protesters have put out a call to converge on the Rockefeller Center Christmas tree lighting event.
Video evidence does not ensure police accountability or an end to brutality. If the justice system doesn't show there are consequences to police violence, then popular resistance must.
In an angry press conference, police union reps pretty much blamed everyone but police officers for the choking death of Eric Garner.
A federal court rules that cops can't arrest you for filming them. But this doesn't end impunity or brutality.