Even the disciplinary history of police officers like Daniel Pantaleo, who was accused of causing Eric Garner’s death with a chokehold on Staten Island, remained secret under state law, prompting an outcry from public defenders, lawyers and advocates for criminal justice reform.

Until now, the New York Police Department has stood firm with its police unions in blocking the release of personnel files, including disciplinary records, which by law must remain confidential under a section of the State Civil Rights Law known as 50-a.

But on Friday, Police Commissioner James P. O’Neill said he would support legislation to make more of the department’s disciplinary files public, after an independent commission found an “almost a complete lack of transparency and public accountability” in the department’s system for investigating misconduct.

“I believe that the law must change,” O’Neill said in a news conference after the commission released its report. “We need to put out names, charges, documents and outcomes.”

The commissioner’s statement came as the efforts to overhaul the law have gained new life in the state Legislature, where Democrats control both chambers as well as the governor’s office. Previous attempts to change the law had been stymied by a Republican majority in the Senate.

Mayor Bill de Blasio came out in favor of changing the law in 2016 to allow for more transparency.

O’Neill’s remarks Friday were immediately condemned by the city’s largest police union, which said the release of disciplinary records would “shred the confidentiality protections for police personnel records” and “will put all New Yorkers in jeopardy.”

Friday’s events were the latest developments in a national fight over making law enforcement disciplinary records public. In California, police unions across the state are suing to block a new law that removes privacy protections for confirmed misconduct.

The independent panel, commissioned by O’Neill in June, found the department’s approach to discipline lacked consistency or structure. Though the panel found no evidence of abuses of power, the Police Department’s lack of standards and guidelines in its disciplinary proceedings made the process susceptible to favoritism or bias.

The process, the commission found, suffered from “a fundamental and pervasive lack of transparency.”

Along with transparency issues, the panel found that the department failed to consistently discipline officers when they made false statements or committed domestic violence.

Civil rights groups have long pushed for changes to the department’s policy and to state law that would allow for more sunlight on police disciplinary proceedings. That includes the public release of documents like calendars of administrative trials, case judgments, and details of sentences, all of which are withheld by the Police Department under the civil rights statute.

In response to the report’s findings, O’Neill said the department would begin releasing trial calendars within 30 to 60 days, and a working group of senior police officials would be asked to ensure that disciplinary proceedings were conducted in a consistent and unbiased manner.

The Legal Aid Society and the New York Civil Liberties Union have brought lawsuits against the department in the past five years pushing for the release of records. Neither of those suits was successful, and in both cases, court rulings upheld and strengthened the department’s interpretation of the civil rights statute.

Christopher Dunn, the Civil Liberties Union’s legal director, welcomed the report’s findings and O’Neill’s promise to support changing the law. Given the Democrat-controlled Legislature, Dunn said, the Police Department’s support for reform could be decisive.

“If the NYPD actively supports it, that would make changing the law much easier,” Dunn said. But he added that it remained to be seen how committed O’Neill and others in the de Blasio administration were to changing the statute.

“It’s fine for them to say it, but we want to see them get aggressive with the legislature and see that 50-a is repealed,” he said.

The Legal Aid Society, which provides free legal representation to the city’s poor, said the panel’s recommendations did not go far enough to open up the department’s proceedings to public scrutiny.

“Until Albany fully repeals 50-a so that disciplinary summaries and other critical information are once again made available for the public to truly hold police officers accountable, we clearly cannot count on the department to police itself,” said Cynthia Conti-Cook, a staff attorney with the society’s Special Litigation Unit.

The department’s lawyers have interpreted the law broadly over the last decade. Critics say they have used it as a catchall to avoid releasing personnel files the police would prefer to keep secret. That interpretation has been upheld by the courts, a development that the panel acknowledged in its report will require legislation to overturn.

The strict limits on police disciplinary records have been on display in the past few months during the administrative proceedings against Pantaleo, the man accused of killing Garner in 2014. His records were eventually leaked to the media, but still, all motions, exhibits and transcripts of court proceedings are considered privileged. Pantaleo’s trial is expected to begin in May.