Participants in a rally for justice are calling on Mayor Bill de Blasio to make sweeping changes at the NYPD.

The National Action Network hosted a rally, spearheaded by Rev. Al Sharpton, at its Harlem headquarters to spread word about what they are calling "police brutality."

Many of Saturday's protesters say that recent encounters with police have violated civil rights, by their use of unnecessary force. They say they plan on protesting peacefully, and will voice their concerns until the mayor addresses the possible issue.

On Wednesday, a bystander filmed a police officer apparently stomping on a Brooklyn man's head as he was being apprehended. In another video that has made headlines for the past week, Eric Garner, of Staten Island, can be seen in an apparent chokehold by an officer as he is placed in handcuffs. He then suffered a fatal heart attack in police custody.

Garner's wife was present at the rally, speaking out for the first time in public since her husband's funeral. She says he was a quiet man who, now after his death, is making a lot of noise.