The Civilian Complaint Review Board is set to prosecute NYPD Officer Daniel Pantaleo in the 2014 “chokehold” death of Eric Garner in Staten Island, becoming the fourth government agency involved in the case.

The NYC board has determined Pantaleo applied a department-banned chokehold on Garner, killing him. It has recommended the NYPD file administrative charges, which could lead to suspension or firing.

On-duty police killings of civilians, as this one was, involve degrees of politics. That is, probes take on issues beyond the case. And no case of police killing in NYC has become more political than Pantaleo’s. That the CCRB has stepped in is an implicit sign that traditional law enforcement agencies — a district attorney’s office, the Justice Department and the NYPD — have made the case a mockery of justice.

Not that it is easy to convict a cop in such cases. In the last 30 years, only one NYPD officer has been convicted: Peter Liang, who accidentally discharged his weapon in Brooklyn complex killing Akai Gurley in 2014.

In Garner’s case, Pantaleo was responding to complaints by local merchants that Garner was selling “loosie,” or untaxed, cigarettes outside their stores. He jumped Garner from behind and used what appeared to be a chokehold to subdue him.

Garner, 43, died at the scene.

Where the CCRB’s potential prosecution of Pantaleo goes is unclear. Historically, the CCRB has been a law enforcement backwater. Although the city charter calls for full police cooperation, when Ray Kelly was commissioner, the NYPD forbade officers from testifying before it. Under an agreement struck toward the end of Kelly’s term with then-City Council Speaker Christine Quinn, the CCRB was empowered to prosecute cases before a police judge, with the NYPD commissioner — in Pantaleo’s case James O’Neill — as the final arbiter.

Pantaleo’s attorney, Stuart London, says the CCRB violated protocol by not interviewing witnesses and Pantaleo, who has been on desk duty since 2014. That indicates it is relying solely on cellphone video that captured the chokehold.

“They made a political decision,” said London. “I question the integrity of the process.”

Would O’Neill dismiss Pantaleo’s case? It hardly seems likely as he is in lockstep with Mayor Bill de Blasio, who might have difficulty absorbing the political fallout.

On the other hand, by the time the case is tried, de Blasio will have long been re-elected.