Dozens of activists and family members gathered in front of Ramarley Graham's home Thursday to mark four years since the teen's fatal shooting at the hands of the NYPD. 

They planned to march 17 miles from the Bronx to One Police Plaza in lower Manhattan to demand Mayor Bill de Blasio and the NYPD fire all of the officers who took part in the 2012 encounter that ended the unarmed 18-year-old's life. 

Since Graham's death, his family says they have endured numerous disappointments and setbacks in their quest to hold police accountable. 

An indictment was dismissed in 2013 against Officer Richard Haste, the police officer who fired the shot that killed Graham. In March, the U.S. Justice Department found there was insufficient evidence to pursue federal charges in the case. 

Between four and 12 officers were involved in the incident, although Haste was the only one who pulled the trigger, Graham's supporters say.

Graham's mother and supporters of the family are now calling on the mayor to step in and take action. 

Haste has already been placed on modified duty, according to the NYPD. The Graham family also received a $3.9 million settlement to end a wrongful death lawsuit against the city.