More than a dozen members of the NYPD will soon testify about their involvement and oversight in the death of Eric Garner as part of a highly unusual public inquiry that seeks to bring further transparency to the 2014 police killing.

The proceeding, which kicks off Monday and is expected to last three weeks, follows years of pressure by Garner’s mother, Gwen Carr, and other police accountability advocates, who allege that the city withheld information and failed to properly investigate the high-profile killing.

Neither Mayor Bill de Blasio nor NYPD Commissioner Dermot Shea will be compelled to testify, as the petitioners initially requested. Instead, the inquiry will feature testimony from several officers directly involved in Garner’s arrest, as well as high-ranking department leaders in the NYPD’s Internal Affairs Bureau.

In the view of the petitioners, the proceeding marks one of the final legal avenues to obtain justice for Garner, who was placed in a chokehold by then-Officer Daniel Pantaleo for allegedly selling untaxed cigarettes in a Staten Island park. While the killing sparked a national movement against excessive police force, it did not result in criminal consequences for Pantaleo or any other officer.

The legal case itself rests on an obscure and largely untested provision of the New York City Charter, which allows groups of citizens to petition the court for a public inquiry into ''any alleged violation or neglect of duty in relation to the property, government or affairs of the city.'' The provision dates back to Boss Tweed-era corruption cases and, according to legal experts, has not resulted in an inquiry in nearly a century.

(Two decades ago, a judge authorized such an inquiry into then-Mayor Rudy Giuliani for sharing sealed criminal records of Patrick Dorismond, an unarmed Black man shot by the NYPD. However, the case settled out of court before proceedings could begin.)

“It’s all to a certain extent writing on a blank slate,” said Alvin Bragg, an attorney for the petitioners, and the presumed frontrunner for Manhattan District Attorney.

That the case has gotten this far, he said, is a testament to the endurance of Carr and other supporters, who fought the city’s efforts to dismiss the inquiry for years. “Not only did we have to bring the suit, we’ve had to vigorously litigate to get to the point we’re out now,” Bragg added.

Lawyers for the de Blasio administration had sought to dismiss the inquiry on the grounds that the mayor and police commissioner do not have a duty to discipline officers who commit misconduct.

“The duty is discretionary,” Law Department attorney Stephen Kitzinger said during oral arguments last summer. “It’s their own prerogative.”

The inquiry is expected to focus on four distinct elements: the stop and use of force against Garner; the alleged filing of false official documents following the arrest; the leaking of Garner’s arrest history and medical conditions shortly after his death; and the alleged failure to provide him medical care following the chokehold.

Prosecutors say they will also take a broad look at the lack of consequences faced by those who played a role in the stop. Although the judge may issue written findings, they will not have the power to discipline any officer or official.

To date, Pantaleo is the only officer who lost his job over Garner’s death — a termination that came five years after the fatal confrontation. Sergeant Kizzy Adonis, one of two NYPD sergeants at the scene, was docked 20 vacation days after pleading guilty to the departmental charge of failure to supervise.

Garner’s family has called on the city to fire a host of other NYPD members involved in the arrest, including Lieutenant Christopher Bannon, who drew outrage after his text message to a subordinate describing Garner’s death as “not a big deal” surfaced during a department trial.

Pantaleo’s partner, Justin D’Amico, will also be called to testify on Monday. Following Garner’s death, D’Amico filed an arrest complaint accusing him of a felony tax law violation, a charge that would have required Garner to have evaded taxes on 10,000 or more cigarettes. Only 95 cigarettes were found in his possession.

In an email, a spokesperson for the Law Department said: “While we don’t believe there is a need for the Summary Inquiry to go forward as so much has already been made public about this tragic event, we look forward to the hearing and satisfying the Court’s order for further transparency.”

A livestream of Monday morning’s hearing can be found here.