The officer has been charged with murder and the FBI and US Justice Department are investigating the shooting, the latest in a series of incidents that have raised questions about US policing and race relations.
Civil rights leaders have called for calm, and many people praised the courage of the witness who filmed the killing and gave the video to the victim's family.
“This is what happens ... when people are willing to step up and do the right thing for the right reasons,” State Representative Justin Bamber told reporters late on Tuesday.
Chris Stewart, an attorney for the victim's family, said the incident is bigger than race.
“It goes to power itself. This was a cop who felt like he could just get away with shooting someone that many times in the back,” Stewart said. “It speaks to the value of human life.”
