Earlier this week, a judge dismissed manslaughter charges against Officer Richard Haste, who killed 18-year-old Ramarley Graham in the teen's bathroom.
The judge blamed mistakes by prosecutors, and the district attorney's office said it will re-file the case.
On Saturday afternoon, parents Constance Malcolm and Francelot Graham will attend a rally in Harlem hosted by the Reverend Al Sharpton's National Action Network.
The ruling Wednesday prompted a courtroom outburst by Malcolm and a vow by prosecutors to still pursue the case.
Malcolm cursed and screamed, "They killed my child!" as it became clear that the judge was about to rule in favor of Haste. Court officers immediately removed her.
When order was restored, Judge Steven Barrett told spectators, "I regret that there are people who are hurt by this" but insisted that a flawed grand jury presentation by prosecutors left him no choice.
As Haste left the courtroom, protesters yelled, "Murderer!" The officer did not speak to reporters.
Haste had been charged in the shooting, which happened during a police operation targeting street-corner drug dealing in the Bronx. He and other officers chased Graham into his family's apartment where the teen was shot at close range.
The victim was struck in the upper chest and collapsed inside a bathroom as his grandmother and younger brother stood nearby. No gun was recovered.
The judge ruled that prosecutors, in giving instructions to grand jurors, had improperly left the impression the jury shouldn't consider testimony by other officers that they radioed Haste in advance to warn him that they thought Graham had a pistol.
Haste testified in the grand jury that the radio transmissions convinced him Graham was armed and dangerous when he shot him in the chest. Jurors also heard evidence that Haste yelled, "Gun! Gun!" as a warning to other officers before opening fire.
"In effect, the grand jury was told communications of other officers were not relevant," the judge said. "With no great pleasure, I'm obliged in this case to dismiss the charges."
The judge stressed that he didn't believe prosecutors deliberately misled the grand jury and he wouldn't bar them from seeking another indictment.
Prosecutors said in a statement that they would either appeal the decision or present the case again to the grand jury.
"It cannot be said more forcefully that we disagree with the court," the statement said.
But Patrick Lynch, president of the Patrolmen's Benevolent Association, said the judge's ruling was the right one.
"We believe the judge made a difficult but correct decision," Lynch said.