Body-worn cameras were supposed to deliver a revolution in transparency and accountability to policing. But in cities across America, the revolution never arrived.

The New York Police Department is undermining investigations into police abuse by refusing to give full access to body-worn camera footage, according to a new report by a city watchdog agency.

The NYPD began rolling out body-worn cameras to officers in 2017, nearly four years after a federal judge found that the department’s stop-and-frisk tactics were unconstitutional and ordered the NYPD to begin piloting the use of body cams.

The cameras are now standard issue in many jurisdictions across the country, seen as a way to provide more objective accounts of police actions and rely less on the recollections of officers or anyone else.

But, as ProPublica has detailed, the NYPD has often refused to share footage with the Civilian Complaint Review Board, the city agency tasked with investigating allegations of excessive force and other misconduct.

In some instances, the NYPD has told CCRB investigators no footage of an incident exists, only for the CCRB to later learn that it does. For example, during one investigation of an incident for which the NYPD said there was no footage, an officer later told investigators that she had her camera on.

Other times, the NYPD has acknowledged footage exists but refused to turn it over, citing privacy issues. In one case, an officer slammed a young man into the pavement, sending him to the hospital with a brain bleed. Seven body cameras worn by officers captured parts of the incident. But the NYPD withheld almost all the footage from CCRB investigators, on the grounds that a minor’s face could be seen in some of it.

The new report, by the Inspector General for the NYPD, which is not part of the department, recommends a straightforward solution: Investigators at the CCRB should have direct access to body-worn camera footage, so they don’t have to rely on the NYPD’s discretion. Police oversight agencies in a number of other cities already have such access.

“Effective and independent police review requires direct access to body-worn camera footage,” the inspector general, Philip Eure, said in a statement. “Oversight agencies cannot hold officers accountable for misconduct and foster greater trust between communities and law enforcement if the police withhold, redact, or delay the production of critical evidence.”

In its response, the NYPD rejected the call to give CCRB investigators full access.

The department emphasized that backlogs of requests for footage — an issue ProPublica has highlighted — have been addressed. The NYPD argued that the report was based on outdated information “about past practices that are no longer applicable.”

But the response gives the false impression that investigators already have the access they are seeking.

In referring to the call for direct access to body-worn camera, or BWC, footage, the NYPD stated: “The CCRB already has access to BWC footage detailed in this recommendation.”

Currently, CCRB investigators have to go through a request process that depends on the NYPD’s cooperation.

“Direct access has, and continues to be, one of the top needs of the CCRB,” the agency’s chair, the Rev. Frederick Davie, said in a statement to ProPublica.

An analysis last year by the CCRB found that investigators got to the bottom of cases — either substantiating allegations or clearing officers of charges — far more often when they were able to review body cam footage.

Two years ago, the NYPD and CCRB arrived at what was supposed to be a solution to the dispute over access to footage. Under the agreement, a CCRB investigator can observe NYPD staff as they search the system. But even then, the NYPD has limited what CCRB investigators can do with what they see. For example, if an investigator sees abuse unrelated to the case in question, the CCRB can’t start an investigation into it.

The inspector general said social distancing and work-from-home measures instituted during the pandemic have hampered the protocol, but that even when fully implemented, the process would “waste limited City time and resources attempting to perfect an imperfect solution.”

As ProPublica has detailed, the NYPD has also often not cooperated with the inspector general’s office itself. A footnote to the new report contained further evidence of that. It said the office sought to interview NYPD officials about body-worn cameras but were rebuffed: “NYPD opted against making any representatives available for a meeting (or meetings).”