NEW YORK (CBSNewYork) — A Queens City Councilman charged Wednesday that the de Blasio administration is trying to cover up police misconduct – opening a potentially explosive new front as the mayor seeks reelection.

“The mayor just wants to cover up any issue of police misconduct,” Councilman Rory Lancman (D-24th) told CBS2 Political Reporter Marcia Kramer.

Lancman is now in a tug of war with the NYPD – threatening a subpoena to get records of a chokehold case in which police Commissioner James O’Neill overturned the finding of an administrative trial judge that the officer was guilty.

“I think the mayor has made a decision that he is going to prevent as much transparency when it comes to police misconduct as possible,” Lancman said. “It goes against his narrative of having reformed the Police Department.”

In the wake of public outrage over the NYPD use of chokeholds – most infamously in the Eric Garner case on Staten Island in 2014 – Lancman wants to codify in the law an internal NYPD policy that has banned chokeholds since the early 1990s.

Lancman wants the use of chokeholds to be a misdemeanor, and he said he needs all the records of the case where O’Neill overturned the disciplinary ruling.

“I need that information as the sponsor of the chokehold prohibition bill,” Lancman said.

The Civilian Complaint Review Board says civil rights law prevents the release about the detective in question.

However, said former CCRB head Richard Emery, “That should not prevent the Police Department, or the CCRB, for that matter, from releasing description details that is not identifiable with the particular police officer — so the public can have confidence in the process and the decisions.”

Mayor Bill de Blasio was asked about the controversy on Monday. He defended O’Neill’s decision and deflected the blame for the lack of transparency on Albany legislators to change the civil rights law.

“Our Albany office was working on it from the beginning of this legislative session,” de Blasio said Monday. “It became clear there was not a pathway.”

Meanwhile, sources told CBS2 that the NYPD, seeking to defend O’Neill’s ruling, sought and received a green light from the detective involved to release a surveillance video – -captured in a reflection outside the elevator where the chokehold was used.