Details from the grand jury that decided not to indict a New York City police officer for the chokehold death of Eric Garner last year will be kept secret, a judge ordered on Thursday.

The organizations and people asking for the information to be publicly released did not show a “compelling” reason, wrote Justice William Garnett of the New York State Supreme Court. Garnett added that if grand jury details were released for “every newsworthy case,” it could lead to pressure — “real or perceived” — on people serving on grand juries down the line.

“What would they use the minutes for?” Garnett wrote. “The only answer which the court heard was the possibility of effecting legislative change. That proffered need is purely speculative and does not satisfy the requirements of the law.”

Letitia James, public advocate for New York City, vowed Thursday afternoon to appeal the decision to keep the Garner grand jury proceedings hidden. James, the New York Civil Liberties Union and other groups had asked the court to release the grand jury’s transcript, along with the evidence shown to the jury members.

“We are disappointed that the court has chosen to perpetuate secrecy rather than promote transparency,” Arthur Eisenberg, legal director for the New York Civil Liberties Union, said in a statement.” In doing so, the court has reinforced the distrust many New Yorkers already feel toward the performance of the criminal justice system in this case.”

A grand jury in December opted not to indict the police officer for the death of Garner, an unarmed New York man who died last summer after being placed in a chokehold. Garner was black, while the officer involved, Daniel Pantaleo, is white.

Widespread outrage followed Garner’s death and the grand jury’s decision, which came not long after a grand jury in Missouri did not indict a white police officer who shot and killed an unarmed black teen in Ferguson. The two incidents sparked a national wave of protests and unrest regarding the treatment African American men receive at the hands of police officers. After the decision in Missouri, the grand jury testimonies and other evidence in the case were released publicly.

Protest groups in Ferguson and New York have asked for special prosecutors to investigate every use of force by a police officer. In response to the demonstrations that followed these grand jury decisions, officials in New York have weighed in on how to handle police shootings. Gov. Andrew M. Cuomo (D) said he wants to appoint independent monitors to investigate every time a police officer kills an unarmed civilian and that officer is not indicted. Eric T. Schneiderman, the state attorney general, has asked Cuomo to let his office investigate and prosecute cases involving unarmed people killed by police.

The state’s top judge, meanwhile, proposed handing over the grand jury proceedings entirely to judges. During an address last month, Jonathan Lippman, chief judge of New York state, also spoke out against the secrecy involved in the grand jury process. He argued that proceedings should be made public in cases where the subject matter is publicly known, the person being investigated has been named and there is already “significant public interest” in the case. Otherwise, he said, the public is left to speculate.

In his order Thursday, Garnett wrote that releasing grand jury testimonies could hinder attempts to get people to testify openly and honestly. He wrote that it is imperative to make sure that witness testimony is “not the subject of public comment or criticism,” which he said could discourage such testimonies.

“Ironically, if courts routinely divulged grand jury testimony, disclosure would largely impact serious and newsworthy cases,” he wrote.

The Richmond County district attorney who oversaw the investigation released a brief statement Thursday supporting the judge’s order.  “We respect and will adhere to Judge Garnett’s well-reasoned decision,” Daniel M. Donovan Jr. said.